DOC: Clarify WIP: prefix workflow; align AI docs with hook

Three fixes so Documentation/AI/ reflects kw-commit-msg.py:

- WIP: is accepted locally (for in-progress commits) and rejected
  at merge by ghostflow-check-main; document this two-layer workflow.
- Remove BUILD: from the prefix table — the hook regex rejects it.
- Consolidate the prefix list in git-commits.md; enforced-code-style.md
  now delegates rather than duplicating.

Author: hjmjohnson

Documentation/AI/enforced-code-style.md

@@ -28,9 +28,8 @@ Do not use `--no-verify` to bypass — the format check exists to keep CI green.
 
 The `kw-commit-msg.py` hook enforces:
 - Subject line ≤78 characters
-- Standard prefix required (`ENH:` `BUG:` `COMP:` `DOC:` `STYLE:` `PERF:` `BUILD:`)
-- `WIP:` is **not** allowed by `ghostflow-check-main` — use `[WIP]` in the
-  PR title instead (see [git-commits.md](./git-commits.md))
+- Approved commit-subject prefix — see
+  [git-commits.md § Prefixes](./git-commits.md#prefixes) for the list
 
 KWStyle also checks that every header has the doxygen `\class` tag. See
 [compiler-cautions.md](./compiler-cautions.md) section 12a for the

Documentation/AI/git-commits.md

@@ -29,14 +29,21 @@ subject should be scannable in `git log --oneline`.
 | `DOC:` | Documentation only |
 | `STYLE:` | Formatting, naming, no logic change |
 | `PERF:` | Performance improvement |
-| `BUILD:` | Build-system / CMake changes |
-
-> **Do not use `WIP:` as a commit-subject prefix.** It is not in the
-> `ghostflow-check-main` allowed list and will reject the PR. To mark a PR
-> as work-in-progress, use a `[WIP]` prefix in the **PR title** (the GitHub
-> "WIP" app gates merging on it) but keep individual commit subjects on a
-> standard prefix like `ENH:` or `BUG:`. When the PR is ready, remove
-> `[WIP]` from the title.
+| `WIP:` | Transient commits for development testing only |
+
+> **`WIP:` on commit subjects is a two-layer opt-in — use it deliberately.**
+> The local `kw-commit-msg.py` hook **intentionally** accepts `WIP:` so
+> developers can commit probe tests, A/B experiments, and other work they
+> know is not suitable for `main` — without renaming the prefix on every
+> iteration. `ghostflow-check-main` (the GitHub App gating PR merge) then
+> rejects any commit whose subject begins with `WIP:`, which is the
+> intended safety net: `WIP:` commits cannot accidentally land on `main`.
+> Before marking the PR ready for review, remove, reword, fixup, or squash
+> `WIP:` commits into standard-prefix commits.
+>
+> To mark an entire PR (rather than individual commits) as
+> work-in-progress, add `[WIP]` to the **PR title** — the GitHub "WIP" app
+> gates merging on that string; remove it when the PR is ready.
 
 ## Commit Message Length