Iteration 2 — VM core (`wovm`)

Format: product/story-iteration-template. Part of Story — one language, one runtime, one database, one binary.

Goals

A C, libc-only virtual machine that loads a .wob bytecode module and executes method calls with the language's memory model enforced: owned objects with deterministic drops, runtime borrow checks at residual sites, and @gc classes collected without stop-the-world pauses.
Arithmetic and text operations execute correctly — the language's first observable behavior.

What to achieve?
- Given a hand-assembled .wob fixture with arithmetic and method calls,
- when wovm loads and runs it,
- then output matches the fixture's expectation and a corrupted image is rejected by the loader before any instruction executes.
What to achieve?
- Given a fixture that acquires conflicting exclusive borrows,
- when it runs,
- then the VM traps with the borrow-violation code, unwinds running every drop, and ASan/Valgrind report zero leaks on both success and trap paths.
What to achieve?
- Given a cyclic @gc object graph that becomes garbage,
- when the collector's budgeted ticks run,
- then the cycle is freed within the configured budget and no pause exceeds the configured slice.

The OCaml compiler (iteration 3) — fixtures here are assembled by the test tool, not compiled.
Threads, shards, mailboxes (iteration 8); any DB or HTTP capability.

The 16-byte object header reserves a shard id now so iteration 8 needs no relayout.
Format contract: docs/plan/oop-vm/00-wob-format.md twinned with runtime/src/wob.h; ~40-op register instruction set, computed-goto dispatch.

Execute the existing plan: docs/superpowers/plans/2026-08-01-wob-format-and-vm-core.md (16 TDD tasks: arena, object model, borrow word, RC + cycle collector, test assembler, validating loader, interpreter, drop-map unwinding, builtins, CLI + just gate).