docs(commit-history): feature-to-cherry-pick reference

- records the workflow: develop on dev, feature prefix as the
  conventional-commit scope, cherry-pick onto master when ready
- prefix registry so two features cannot claim the same prefix; the
  prefix is claimed before the feature's first commit
- cherry-pick log maps dev hashes to the master hashes they produced —
  they differ, and that mapping is what makes a feature traceable or
  revertible as a unit after dev moves on
- notes the db2-keys seam: written pre-convention on
  porch-store-middleware, replayed onto dev, replay verified identical
- work before 2026-08-29 landed by merge; git log --merges covers it

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
(cherry picked from commit 41923eb1f9510ab53804ca8dc6fe30a9a7eac849)

docs/00-git-commit-history.md

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+# Git commit history — features and their cherry-picks
+
+Reference for **which commits carried which feature onto `master`**, so a
+feature can be traced, re-reviewed, or reverted as a unit long after the
+history it was written in has moved on.
+
+## The workflow this file records
+
+1. **Development happens on `dev`.** Not on `master`, and not on a fresh
+   branch per feature.
+2. **Every commit on `dev` carries a feature-specific unique prefix**, written
+   as the conventional-commit scope — `feat(db2-keys): …`, `fix(db2-keys): …`.
+   The scope, not a bare leading word, so the repo keeps the `feat`/`fix`/`docs`
+   type it has used throughout. One prefix per feature, reused by every commit
+   belonging to it, which makes a feature's commits selectable with
+   `git log --grep` without reading a single diff.
+3. **When the feature is ready** — complete, not merely green — `git checkout
+   master` and **cherry-pick** that feature's commits, in order.
+4. **Record the result below**: the `dev` hashes, the `master` hashes the
+   cherry-pick produced, and the date. The two differ — a cherry-pick makes new
+   commits — and that mapping is the whole reason this file exists.
+
+Ready means the same gate as always: no half-implemented feature reaches
+master. An annotation the compiler accepts but does not honour counts as
+broken, however green the suite.
+
+## Prefix registry
+
+One row per feature. The prefix is claimed here before its first commit, so two
+features cannot collide.
+
+| Prefix | Feature | Status |
+| --- | --- | --- |
+| `commit-history` | this file and the workflow it records | ✅ on `dev` |
+| `db2-keys` | databasev2 2 — `resident: keys` storage and readers | on `dev` (`125bd09`, `08abd09`, `0c97fa4`, `f606fc9`). **Not ready**: the loader still refuses the annotation, and updates on such a table are refused rather than implemented |
+
+## Cherry-picks onto master
+
+Newest first. `dev` hash is the original; `master` hash is what the cherry-pick
+produced.
+
+| Date | Prefix | Feature | `dev` → `master` |
+| --- | --- | --- | --- |
+| — | — | *nothing cherry-picked onto master under this convention yet* | — |
+
+## Before this convention
+
+Work up to 2026-08-29 landed on `master` by **merging** feature branches, so
+those commits keep their original hashes and have no entry here.
+`git log --merges master` is the record for that period.
+
+The `db2-keys` commits are the seam: they were written on
+`porch-store-middleware` before this convention (`18ce4d5`, `f9c36ef`,
+`11a92df`, `91411ae`) and were replayed onto `dev` with prefixed titles. The
+replay was verified identical, not merely applied — `git diff` between the two
+branches over `database/`, `runtime/` and `docs/stories/` is empty.