docs(rt2): track-wide brainstorm — all five iterations ready, graph remapped

- spec 2026-09-01-runtime-v2-design.md: the one principle (PULL — a
  child is fds, the net verbs drive them; runtime-v2 adds acquisition
  verbs, never transport), the full surface (ids 97+: spawn/spawn_pty/
  wait_dl/signal/resize, signal.on delivering the sig number, term.raw/
  restore with runtime-guaranteed restore, send_fd/recv_fd/connect_unix),
  actor-owned lifecycle, mechanics notes, refusals by name
- push transport rejected with reasons recorded (mailbox-cap collision,
  new delivery machinery); death-notice verb refused (a two-line fiber
  composes wait_dl)
- five stories flip readiness: ready; fork sections rewritten as settled
- graph section 6 remapped: pull broke the 1->2->3 chain — only 1->2
  remains; 3, 4, 5 and the VTE grid startable alone today
- board section + registry follow; linkcheck 0 broken

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
(cherry picked from commit d313cdeebbe53c83b83f31f4480631568d9d0743)

docs/00-dependency-graph.md

@@ -322,7 +322,8 @@ exists to make visible. Streaming responses' runtime prerequisites
 The tmux study's gaps, remapped as buildable edges now that iteration 42
 landed. Every yellow node is an iteration of the
 [runtime-v2 track](stories/runtime-v2/00-story.md) ("the runtime beyond
-sockets", its own folder since 2026-09-01), brainstormed on demand —
+sockets"), ALL `readiness: ready` since the track-wide brainstorm
+([spec](superpowers/specs/2026-09-01-runtime-v2-design.md), 2026-09-01) —
 [1 streaming subprocess](stories/runtime-v2/01-streaming-subprocess.md) ·
 [2 PTY](stories/runtime-v2/02-pty.md) ·
 [3 signals as events](stories/runtime-v2/03-signals-as-events.md) ·
@@ -351,21 +352,22 @@ flowchart TD
 
     I42w --> GSTREAM
     GSTREAM --> GPTY
-    GPTY --> GSIG
-    GSTREAM --> GVTE
     GPTY --> WMUX
     GSIG --> WMUX
     GTERMIOS --> WMUX
     GFDPASS --> WMUX
     GVTE --> WMUX
-    TINFO -.settled at brainstorm.-> WMUX
+    TINFO -.settled at wmux's brainstorm.-> WMUX
     TMONO -.v2.-> WMUX
 ```
 
-Sibling reuse, for the record: the alacritty study's Wayland stage D
+**Remapped by the 2026-09-01 track brainstorm** (pull transport: a child
-reuses GFDPASS + GVTE; the zen CDP driver shares GSTREAM only; skillhost
+is fds, the net verbs drive them): the old 1→2→3 chain broke — signals
-(28) consumes GSTREAM's stdin transport. GTERMIOS and GFDPASS have no
+never needed PTY, only the resize pairing, and the VTE grid needs no
-incoming edges — startable any time, alone.
+subprocess (a replay corpus feeds it). Only 1 → 2 remains chained;
+**3, 4, 5 and the grid are all startable alone, today.** Sibling reuse:
+the alacritty Wayland stage reuses GFDPASS + GVTE; the zen CDP driver
+shares GSTREAM only; skillhost (28) consumes GSTREAM's stdin transport.
 
 ## Maintenance rule
 

docs/00-git-commit-history.md

@@ -46,7 +46,7 @@ features cannot collide.
 | `query-corpus` | databasev2 query-grammar corpus #1 | on `dev` (`4c82461`). Conclusion was "no new grammar needed" |
 | `lang42` | iteration 42 — bounded subprocess: `proc.run` bounded + parked (pidfd, caps, ceiling, owner-bound reaping), `proc.run_dl`; carries the alacritty/tmux/zen parity studies and the porch dependency-graph section from the same sweep | ✅ on `master` 2026-09-01 |
 | `wmux` | the wmux track (`docs/stories/wmux/`, iteration 1 was language 43) — the terminal multiplexer, first of the softwares built with writeonce; story + gap-chain remap first, code follows gap by gap | on `dev` 2026-09-01 |
-| `rt2` | the runtime-v2 track (`docs/stories/runtime-v2/`) — the runtime beyond sockets: streaming subprocess, PTY, signals-as-events, termios, fd passing; five refine stories, wmux is the driving workload | on `dev` 2026-09-01 |
+| `rt2` | the runtime-v2 track (`docs/stories/runtime-v2/`) — the runtime beyond sockets: streaming subprocess, PTY, signals-as-events, termios, fd passing; all five `readiness: ready` (track-wide spec 2026-09-01), wmux is the driving workload | on `dev` 2026-09-01 |
 
 ## Cherry-picks onto master
 

docs/stories/00-status.md

@@ -1181,17 +1181,22 @@ this track adds the missing third — **processes, terminals, signals** —
 five builtin-sized seams, each `runtime/src/` work with a `types.ml` row
 as its whole compiler cost (the iteration 42 precedent). Iteration 42
 (bounded subprocess, ✅ on `master` 2026-09-01) opened the arc from the
-language track before it had a name. Build order 1 → 2 → 3; 4 and 5
+language track before it had a name. **All five `readiness: ready`** —
-startable alone. All ⬜ `refine`; edges in
+one track-wide brainstorm settled every fork
-[dependency graph section 6](../00-dependency-graph.md).
+([spec](../superpowers/specs/2026-09-01-runtime-v2-design.md),
+2026-09-01). The keystone decision: PULL transport — a child is fds and
+the existing net verbs drive them, so no new transport machinery exists
+anywhere in the track, and the old 1→2→3 chain broke. Only 1 → 2
+chained; 3, 4, 5 startable alone. Plan per iteration, written when it
+starts. Edges in [dependency graph section 6](../00-dependency-graph.md).
 
 | # | Iteration | State |
 | --- | --- | --- |
-| 1 | [streaming subprocess](runtime-v2/01-streaming-subprocess.md) | ⬜ `refine` — 42's named follow-up: long-lived child, output as events, stdin, exit notice. Five forks (verb shape, push-vs-pull transport, the mailbox-cap collision, stdin backpressure, idle-deadline semantics). First up |
+| 1 | [streaming subprocess](runtime-v2/01-streaming-subprocess.md) | ⬜ ready — `proc.spawn -> Child{id,in,out,err}` (fds driven by the net verbs; kernel pipe = backpressure), `proc.wait_dl`, `proc.signal`; actor-owned lifecycle, 42's sweeps. First up |
-| 2 | [PTY](runtime-v2/02-pty.md) | ⬜ `refine` — openpty + controlling terminal + resize; `.dev/reference/tmux` `spawn.c`/`fdforkpty.c` is the reading |
+| 2 | [PTY](runtime-v2/02-pty.md) | ⬜ ready, after 1 — `proc.spawn_pty(cmd, args, cols, rows)` (master raw, in==out), `proc.resize`; `-lutil` link check flagged |
-| 3 | [signals as events](runtime-v2/03-signals-as-events.md) | ⬜ `refine` — SIGWINCH/SIGCHLD as mailbox messages; signalfd lean; the seam 42 deferred to its real consumer |
+| 3 | [signals as events](runtime-v2/03-signals-as-events.md) | ⬜ ready, **startable alone** — `signal.on(sig, addr)` delivering the sig number as a scalar; signalfd on shard 0's plane; TERM/INT refused by name |
-| 4 | [termios adoption](runtime-v2/04-termios.md) | ⬜ `refine`, **startable alone** — raw mode + guaranteed restore on the process's own tty |
+| 4 | [termios adoption](runtime-v2/04-termios.md) | ⬜ ready, **startable alone** — `term.raw(fd)`/`term.restore(fd)`; restore is a runtime obligation (unwind/stop), no wrecked tty ever |
-| 5 | [fd passing](runtime-v2/05-fd-passing.md) | ⬜ `refine`, **startable alone** — SCM_RIGHTS over unix sockets; detach/attach's foundation |
+| 5 | [fd passing](runtime-v2/05-fd-passing.md) | ⬜ ready, **startable alone** — `net.send_fd`/`net.recv_fd` (one fd, SCM_RIGHTS) + `net.connect_unix` (38 pending, verified) |
 
 ### ▸ wmux — the terminal multiplexer track
 

docs/stories/runtime-v2/00-story.md

@@ -34,9 +34,14 @@ cross a unix socket. Five seams, each builtin-sized, each in
 | 4 | [termios adoption](04-termios.md) | the process's OWN tty into raw mode and back — adopting a terminal it was given |
 | 5 | [fd passing](05-fd-passing.md) | SCM_RIGHTS over unix sockets — detach/attach's foundation, and the Wayland stage's later |
 
-Build order is 1 → 2 → 3 (each leans on the last); 4 and 5 have no
+All five are `readiness: ready` since the track-wide brainstorm
-incoming edges and are startable alone. Edges live in
+([spec](../../superpowers/specs/2026-09-01-runtime-v2-design.md),
-[dependency graph section 6](../../00-dependency-graph.md).
+2026-09-01), which also settled the build order: only 1 → 2 is chained
+(spawn_pty extends spawn's plumbing); **3, 4 and 5 are startable alone,
+today** — the pull-transport decision (a child is fds; the net verbs
+drive them) broke the old 1→2→3 chain. Edges live in
+[dependency graph section 6](../../00-dependency-graph.md); each
+iteration writes its own implementation plan when it starts.
 
 ## The driving workload
 

docs/stories/runtime-v2/01-streaming-subprocess.md

@@ -2,12 +2,14 @@
 track: runtime-v2
 iteration: "1"
 status: pending
-readiness: refine
+readiness: ready
 ---
 
 # runtime-v2 1 — streaming subprocess: a long-lived child as a peer
 
 > Part of [Story — runtime-v2: the runtime beyond sockets](00-story.md).
+> Spec: [`2026-09-01-runtime-v2-design.md`](../../superpowers/specs/2026-09-01-runtime-v2-design.md)
+> (track-wide brainstorm, approved 2026-09-01 — the forks below are settled).
 > Iteration [42](../language-runtime-database/42-bounded-subprocess.md)'s
 > named follow-up, promoted to this track's opening slice. 42 built the
 > machinery a streaming form reuses whole: the `wo_child` registry, the
@@ -21,33 +23,31 @@ readiness: refine
 > actor as it happens, stdin must reach the child, and exit must arrive
 > as an event — all without violating a single 42 guarantee.
 
-## Info — the forks (open; why this is `refine`)
+## Info — the forks, settled (brainstorm 2026-09-01)
 
-1. **Verb shape.** A new `proc.spawn(cmd, args, …)` returning a child
+1. **Verb shape: `proc.spawn(cmd, args) -> ?Child`** — a new verb, and
-   HANDLE, versus spawn-options on `proc.run_dl`. Sub-fork: the handle
+   the handle is a RECORD, not an actor: `Child {id, in, out, err}`,
-   as an actor address (the child looks like an actor — `send` to feed
+   all Int-shaped, joining the predeclared records.
-   stdin, `monitor` for exit, iteration 24 machinery free) versus an
+2. **Transport: PULL, and it already exists.** The child's fds are
-   opaque scalar with its own verb family.
+   ordinary conn-like values; `net.read_dl`/`net.write_dl`/`net.close`
-2. **Output transport.** PUSH — stdout/stderr chunks delivered as
+   drive them unchanged through the park plane. This iteration adds NO
-   `Bytes` messages into the owner's mailbox (the fd-event pattern) —
+   transport code at all — only acquisition, ownership and exit.
-   versus PULL — a `read`-style verb the fiber parks on, the
+3. **The mailbox-cap collision never starts** — nothing is pushed. The
-   `net.read_dl` mould. Push composes with actors; pull composes with
+   kernel pipe is the backpressure: an owner that stops reading makes
-   backpressure.
+   the child block on write, exactly tmux under a slow client.
-3. **The mailbox-cap collision** — the fork that decides whether push is
+4. **stdin mirror settled by the same move**: `net.write_dl` on
-   viable at all: a chatty child versus `wo_mailbox_cap`'s fail-fast
+   `child.in` parks with a deadline; torn-write semantics as on sockets.
-   1024. Drop chunks? Kill the child by name? Or stop reading the pipe
+5. **Bounds:** the idle deadline is `read_dl`'s per-call ms; output caps
-   and let the KERNEL buffer be the backpressure (the lean — the child
+   are the caller's read sizes (no runtime buffer exists); exit is
-   blocks on a full pipe exactly as it would under a slow tmux).
+   `proc.wait_dl(id, ms) -> ?Int` parking on the slot's pidfd — one
-4. **stdin and its mirror.** Child not reading, pipe full: park the
+   waiter per id, a second refuses by name. `proc.signal(id, sig)`
-   writing fiber with a deadline (the `net.write_dl` mould) versus
+   completes the surface. A death-notice verb is refused: a two-line
-   refuse at a byte cap.
+   fiber composes `wait_dl` into an event.
-5. **Bounds semantics shift.** Total-output cap and total deadline stop
-   meaning anything for a shell that runs for days — per-chunk caps and
-   an IDLE deadline replace them; exit notification as a monitor-style
-   death notice carrying the code, versus a blocking `wait` verb.
 
-Ownership does not fork: 42's rule stands — the owner unwinding kills
+Ownership (stated, not forked): the spawning ACTOR owns the child (the
-the child; engine stop kills them all; a zombie or an orphan is a bug.
+program, when spawned outside one). Actor death, engine stop and
+`wo_vm_destroy` kill, reap and close — 42's doctrine, streaming edition.
+Ceiling stays 32 per shard, failing closed by name.
 
 ## Acceptance sketch (firmed at brainstorm)
 

docs/stories/runtime-v2/02-pty.md

@@ -2,7 +2,7 @@
 track: runtime-v2
 iteration: "2"
 status: pending
-readiness: refine
+readiness: ready
 ---
 
 # runtime-v2 2 — PTY: a child that believes it owns a terminal
@@ -19,19 +19,19 @@ readiness: refine
 > `compat/fdforkpty.c` (~450 lines of C covering five platforms; Linux
 > alone is far smaller).
 
-## Info — the forks (open)
+## Info — the forks, settled (brainstorm 2026-09-01; spec:
+[`2026-09-01-runtime-v2-design.md`](../../superpowers/specs/2026-09-01-runtime-v2-design.md))
 
-1. **Surface.** A `pty: true` option on iteration 1's spawn verb (the
+1. **Separate verb**: `proc.spawn_pty(cmd, args, cols, rows) -> ?Child`
-   lean — one spawn shape, two transports) versus a separate
+   — its own builtin id (static arity table stays static), same Child
-   `proc.spawn_pty`.
+   record with `in` and `out` both the master fd, `err` nil.
-2. **Resize.** A verb on the handle (`resize(cols, rows)` → TIOCSWINSZ)
+2. **Resize ships HERE**: `proc.resize(id, cols, rows)` → TIOCSWINSZ on
-   — needed the moment [3](03-signals-as-events.md) delivers SIGWINCH.
+   the slot; refusal by name on a pipe child.
-   The fork is only whether it ships here or with 3.
+3. **Transport settled by iteration 1's pull decision** — the master fd
-3. **The master fd's transport** is settled by iteration 1's fork 2 —
+   is driven by the existing net verbs, nothing new.
-   whatever won there carries the PTY master identically.
+4. **Master raw by default, no knobs** — until a consumer asks by name.
-4. **Encoding edge.** A PTY master delivers the child's output with tty
+   (`openpty` may need `-lutil` — the plan verifies the link line
-   post-processing (ONLCR and friends): raw the master by default versus
+   before assuming.)
-   expose termios knobs. Lean: raw, no knobs, until a consumer asks.
 
 ## Acceptance sketch
 

docs/stories/runtime-v2/03-signals-as-events.md

@@ -2,7 +2,7 @@
 track: runtime-v2
 iteration: "3"
 status: pending
-readiness: refine
+readiness: ready
 ---
 
 # runtime-v2 3 — signals as events: SIGWINCH into a mailbox
@@ -21,25 +21,23 @@ readiness: refine
 > once: the stop flag is a signal made safe by latching. This iteration
 > generalizes that shape without handing user code a signal handler.
 
-## Info — the forks (open)
+## Info — the forks, settled (brainstorm 2026-09-01; spec:
+[`2026-09-01-runtime-v2-design.md`](../../superpowers/specs/2026-09-01-runtime-v2-design.md))
 
-1. **Registration surface.** `signal.on(SIGWINCH, addr, msg)` in the
+1. **`signal.on(sig, addr)`** — a standing subscription delivering the
-   `time.after` mould (the msg MOVES to the runtime, delivered on
+   SIGNAL NUMBER as a scalar message. No moved-message ownership rules:
-   arrival) versus a process-level subscription table in `wo.toml`.
+   scalars copy, so a repeating SIGWINCH needs no per-delivery payload.
-   Lean: the builtin — dynamic, one consumer today.
+2. **signalfd on shard 0's plane** — one more registered fd with a
-2. **Delivery mechanics.** `signalfd` on shard 0's plane (a signal
+   sentinel `user_data` (the wake-eventfd precedent); reads drain
-   becomes an fd event — no async-signal-safety questions at all, the
+   `signalfd_siginfo` records and fan out ordinary sends.
-   kernel-primitive taste) versus a latch array swept like deadlines.
+3. **Offerable set: SIGWINCH, SIGCHLD, SIGHUP, SIGUSR1, SIGUSR2.**
-   Lean: signalfd; the runtime is Linux-first and the plane already
+   SIGTERM/SIGINT registration is refused by name — the stop latch
-   multiplexes fds.
+   stays the engine's, iteration 40 is load-bearing.
-3. **Which signals are offerable.** SIGWINCH and SIGCHLD certainly;
+4. **Coalescing disclosed, not sequenced** — what SIGWINCH consumers
-   SIGTERM/SIGINT stay the ENGINE's (the stop latch is load-bearing —
+   expect anyway.
-   iteration 40's drain). The fork is whether user registration for the
+
-   stop signals is refused by name or layered before the latch.
+Also settled: this iteration is STANDALONE — the old edge from PTY was
-4. **Coalescing.** Signals coalesce in the kernel; a mailbox message per
+only the resize pairing; signalfd needs nothing from iteration 2.
-   delivery can't promise one-per-resize. Disclose coalescing (lean —
-   it is what SIGWINCH consumers expect anyway) versus sequence-number
-   them.
 
 ## Acceptance sketch
 

docs/stories/runtime-v2/04-termios.md

@@ -2,7 +2,7 @@
 track: runtime-v2
 iteration: "4"
 status: pending
-readiness: refine
+readiness: ready
 ---
 
 # runtime-v2 4 — termios adoption: raw mode on a terminal we were given
@@ -17,20 +17,18 @@ readiness: refine
 > including a trap. A terminal left raw is the classic way a program
 > makes a user's shell unusable.
 
-## Info — the forks (open)
+## Info — the forks, settled (brainstorm 2026-09-01; spec:
+[`2026-09-01-runtime-v2-design.md`](../../superpowers/specs/2026-09-01-runtime-v2-design.md))
 
-1. **Surface size.** Exactly two verbs — `term.raw()` returning a
+1. **Exactly two verbs**: `term.raw(fd)` and `term.restore(fd)`. Saved
-   restore token and `term.restore(token)` (the lean: wmux needs
+   termios live in a per-shard table keyed by fd (one thread — no
-   nothing else; tmux itself uses little more than `cfmakeraw`) —
+   locks); double-raw on one fd refuses by name; no flag knobs.
-   versus exposing termios flag knobs. YAGNI says two verbs and a
+2. **Restore is a RUNTIME OBLIGATION.** Fiber unwind, engine stop and
-   refusal for the rest.
+   `wo_vm_destroy` restore every saved tty, newest first — "no orphan"
-2. **Restore guarantee.** Tie restoration to the unwind machinery (the
+   has its terminal-state sibling: no wrecked tty, ever, trap paths
-   42 ownership pattern: fiber dies, terminal restored — a runtime
+   included.
-   obligation) versus caller's-problem-with-a-doc-note. Lean: runtime
+3. **fd-taking from day one** — a tty received via
-   obligation; "no orphan" has a terminal-state sibling: no wrecked tty.
+   [5](05-fd-passing.md) works without the verb growing an argument
-3. **Scope.** stdin only, versus any tty fd (a client adopting a tty it
-   received via [5](05-fd-passing.md) — the wmux SERVER's need). This
-   fork decides whether the verb takes an fd argument now or grows one
    later.
 
 ## Acceptance sketch

docs/stories/runtime-v2/05-fd-passing.md

@@ -2,7 +2,7 @@
 track: runtime-v2
 iteration: "5"
 status: pending
-readiness: refine
+readiness: ready
 ---
 
 # runtime-v2 5 — fd passing: SCM_RIGHTS over the unix socket
@@ -22,21 +22,19 @@ readiness: refine
 > SCM_RIGHTS ancillary data is the only mechanism, and it is runtime
 > work by nature.
 
-## Info — the forks (open)
+## Info — the forks, settled (brainstorm 2026-09-01; spec:
+[`2026-09-01-runtime-v2-design.md`](../../superpowers/specs/2026-09-01-runtime-v2-design.md))
 
-1. **Surface.** `net.send_fd(conn, fd)` / `net.recv_fd(conn)` — two
+1. **Two verbs, fd travels alone**: `net.send_fd(conn, fd) -> Bool` /
-   verbs, fd travels alone (the lean; tmux sends its imsg header as
+   `net.recv_fd(conn) -> ?Int` — `sendmsg` + SCM_RIGHTS, fixed
-   ordinary bytes beside it) — versus fd-attached-to-a-message framing
+   ancillary buffer; framing stays the caller's ordinary bytes (the
-   in the runtime.
+   tmux imsg shape, composed in `.wo`).
-2. **What arrives.** The received fd as an opaque scalar the existing
+2. **A received fd is a plain Int** every existing fd verb accepts —
-   `net.read`/`net.write`/termios verbs accept (lean — every fd verb
+   net reads/writes, termios adoption included.
-   already takes an Int-shaped conn) versus a new wrapped type.
+3. **This iteration CARRIES `net.connect_unix(path) -> Int`** —
-3. **The unix-socket client side.** Iteration 38's `net.connect` covers
+   iteration 38 verified pending at brainstorm time, not assumed.
-   outbound TCP; the CLIENT half of a unix-socket connection may or may
+4. **One fd per message**, refusal by name past it; non-unix sockets
-   not exist by then — this iteration carries `net.connect_unix` if 38
+   refuse by name; multi-fd arrays wait for a consumer.
-   has not landed it first. Verify at brainstorm, not assumed.
-4. **Bounds.** One fd per message, refusal by name past it (lean),
-   versus SCM_RIGHTS' multi-fd arrays. YAGNI: no consumer sends two.
 
 ## Acceptance sketch
 

docs/superpowers/specs/2026-09-01-runtime-v2-design.md

@@ -0,0 +1,100 @@
+# runtime-v2 — the runtime beyond sockets, all five iterations settled
+
+> Brainstormed and approved 2026-09-01, one pass across the whole track:
+> [runtime-v2](../../stories/runtime-v2/00-story.md) iterations 1–5.
+> Scope settled: PULL transport (a child is fds; the net verbs already
+> drive them), `wait_dl` over death notices, PTY as a spawn variant,
+> signals via signalfd delivering the signal number, termios as two
+> fd-taking verbs with runtime-guaranteed restore, fd passing as two
+> verbs plus `net.connect_unix`. This spec is track-wide; each iteration
+> gets its own implementation plan when it starts.
+
+## The one principle
+
+**A child is fds plus a registry slot — runtime-v2 adds ACQUISITION
+verbs, never new transport.** `net.read_dl`, `net.write_dl` and
+`net.close` already park on any fd through the shard plane (POLL_ADD is
+fd-agnostic; pipes and PTY masters qualify today). So:
+
+- Backpressure is the kernel pipe. An owner that stops reading makes
+  the child block on write — exactly tmux under a slow client. The
+  mailbox-cap collision never starts because nothing is pushed.
+- The idle deadline is `read_dl`'s own per-call ms. Total-output caps
+  disappear because no runtime buffer exists — the caller's read sizes
+  ARE the bound.
+- A wmux pane actor is chat's Reader actor with a different fd.
+
+The rejected alternative, recorded: PUSH (child output as mailbox
+messages) required new delivery machinery in `vm.c`, a policy for the
+`wo_mailbox_cap` collision (drop, kill, or park — each wrong somewhere),
+ordering rules across two streams, and per-chunk allocation. Everything
+pull gets from three landed iterations, push would rebuild.
+
+## The surface
+
+New builtin ids from 97 up. Every id is FOUR registrations — `wob.h`
+enum, `loader.c` arity table, `builtin.c` dispatch range, `types.ml`
+stdlib row — the iteration 42 lesson; missing one reads as "unknown
+stdlib builtin" from a valid image. No `.wob` version bump (the 38/42
+precedent). `Child` joins the predeclared records (`types.ml`
+`stdlib_records`): `id`, `in`, `out`, `err` — all Int-shaped; the fds
+are ordinary conn-like values every existing fd verb accepts.
+
+| Verb | Contract |
+| --- | --- |
+| `proc.spawn(cmd, args) -> ?Child` | iteration 1. Pipes on all three stdio fds, parent ends `O_NONBLOCK`; the registry slot is claimed (ceiling 32/shard, fails closed by name) and OWNED (below) |
+| `proc.wait_dl(id, ms) -> ?Int` | iteration 1. Parks on the slot's pidfd (the 42 machinery); the exit code, or nil at the deadline. ONE waiter per id — a second concurrent wait refuses by name |
+| `proc.signal(id, sig)` | iteration 1. `pidfd_send_signal` through the slot — no pid-reuse race |
+| `proc.spawn_pty(cmd, args, cols, rows) -> ?Child` | iteration 2. openpty; child on the slave as controlling terminal; `in` and `out` are both the master, `err` is nil; master raw by default, no knobs |
+| `proc.resize(id, cols, rows)` | iteration 2. TIOCSWINSZ on the slot's master; refusal by name on a pipe child |
+| `signal.on(sig, addr)` | iteration 3. Standing subscription; delivery is an ordinary send of the SIGNAL NUMBER as a scalar (scalars copy — no moved-message ownership rules). Offerable: SIGWINCH, SIGCHLD, SIGHUP, SIGUSR1, SIGUSR2. SIGTERM/SIGINT refused by name — the stop latch stays the engine's (iteration 40 is load-bearing). Kernel coalescing disclosed, not sequenced |
+| `term.raw(fd)` / `term.restore(fd)` | iteration 4. Save termios into the shard table, `cfmakeraw`, restore from the table. Restore is a RUNTIME OBLIGATION: fiber unwind, engine stop and `wo_vm_destroy` restore every saved tty, newest first. fd-taking from day one — a tty received via iteration 5 works |
+| `net.send_fd(conn, fd) -> Bool` | iteration 5. `sendmsg` + SCM_RIGHTS, exactly one fd, fixed ancillary buffer; refusal by name on a non-unix socket or a second fd |
+| `net.recv_fd(conn) -> ?Int` | iteration 5. The received fd as a plain Int; nil when the peer sent none |
+| `net.connect_unix(path) -> Int` | iteration 5 carries it — iteration 38 (`net.connect`) has not landed; verified pending, not assumed |
+
+## Lifecycle — 42's doctrine, streaming edition
+
+The `wo_child` slot grows: pid, pidfd, owner, and the fds the runtime
+must close if the owner never does. **Owner is the spawning ACTOR when
+one exists, else the program.** Actor death (iteration 24's dead mark),
+engine stop, and `wo_vm_destroy` each sweep: kill via pidfd, reap,
+close the slot's fds, restore any termios the shard saved. The
+per-shard ceiling stays 32; a zombie, an orphan, or a wrecked tty is a
+bug by definition. `wait_dl` parking reuses `fb->dl_active`/`dl_at`
+and parks on the pidfd directly — no epoll bundle needed for a single
+fd.
+
+## Mechanics notes (for the plans)
+
+- signalfd joins shard 0's plane as one more registered fd with a
+  sentinel `user_data`, the wake-eventfd precedent in `park.c`; reads
+  drain `signalfd_siginfo` records and fan out sends.
+- The termios table is per-shard (one thread — no locks), keyed by fd;
+  double-raw on one fd refuses by name.
+- Raw syscalls wherever glibc 2.35 lacks wrappers (the 42 rule);
+  `signalfd` and `openpty` are fine (`openpty` needs `-lutil` — check
+  the Makefile link line before assuming).
+- Each iteration's gate legs: the 42 batteries repeat — fd-flat churn,
+  stop/unwind reaping, refusals asserted verbatim — plus the
+  iteration's own proof (PTY prompt bytes, SIGWINCH round trip, termios
+  restore-after-trap, fd-across-socket byte echo).
+
+## Sequencing (the graph remap this settles)
+
+Pull transport cuts the old 1→2→3 chain: signals never needed PTY, only
+the resize PAIRING. Edges now: **1 → 2** (spawn_pty extends spawn's
+plumbing); **3, 4, 5 startable alone, today**; the VTE grid is wmux's
+own `.wo` work, also standalone (a replay corpus needs no subprocess).
+wmux 1 consumes all five plus the grid.
+
+## Out of scope, by name
+
+- PUSH delivery of child output — rejected above, revisit only with a
+  consumer pull cannot serve.
+- Death notices (`proc.watch`) — a two-line fiber composes `wait_dl`
+  into an event; build it in `.wo`, not in C.
+- termios knobs beyond raw/restore; multi-fd SCM_RIGHTS arrays;
+  sequence-numbered signals; PTY termios shaping — each waits for a
+  named consumer.
+- SIGTERM/SIGINT user handling — permanently the engine's.