epic #470 C14: retire the core-decoupling ratchet; stacked on #808

[Weegy]

Epic #470 C14. Stacked on #808 (C13) — retarget to main once that merges.

The extraction is complete, so the guard that protected it is removed.

Why now

The core-decoupling ratchet was scaffolding for a migration in flight. It made the
file inventory's staleness survivable: a checklist goes stale on contact, a count does
not. It also stopped core re-acquiring a dependency mid-extraction, the realistic
failure mode for a multi-week epic touching ~200 files.

Both jobs are done. The Dev Platform lives in byte5ai/omadia-dev-platform, and C13
drove the count to 0 and pinned it there. What is left is a CI job that can only ever
pass and a number sitting in a JSON file for someone to edit. Reintroducing that
coupling is an ordinary architectural decision now — it should be argued for in
review, not deterred by a counter.

Its full run, measured

Date	Total	Milestone
2026-07-30	3,303	Landed with the epic (#539)
2026-08-07	3,448	Peak
2026-08-20	214	C10 — the ~49k LOC flip
2026-08-20	0	C13 — pinned permanently
2026-08-21	—	C14 — removed

Removed

• scripts/check-core-decoupling.mjs (351 lines)
• scripts/check-core-decoupling.test.mjs (103 lines, the colocated detector test)
• specs/470-dev-platform-plugin/decoupling-baseline.json
• CI job core decoupling ratchet (#470) in .github/workflows/ci.yml, including its
  Ensure ripgrep step, the TOTAL 0 grep and the detector-test step

No npm script referenced the checker (there is no root package.json, and neither
middleware/ nor web-ui/ wired it up), so nothing else had to be unhooked.

Not a silent CI change

Two things were checked before deleting the job, because "removing a job" and
"removing a required job" have very different consequences:

• It is not a required status check. main's protection requires
  middleware (lint + typecheck + test), web-ui (lint + typecheck + vitest),
  schema (migrations on pgvector) and the two audit (high+critical block) legs —
  and nothing else. Worth flagging: the job's own comment claimed it was "kept for
  continuity as a required check". Branch protection disagrees. The comment was
  wrong, not the API. Nothing needs changing in protection settings for this to merge.
• Nothing declared needs: decoupling. No job in any workflow waited on it, so no
  branch can end up blocked on a check that will never report.

Docs and dangling comments

Three comments in middleware/ used the ratchet as a live analogy and would have
pointed at a deleted path (check-test-typecheck.mjs, check-test-file-durations.mjs,
staticPublicPathsClosedSet.test.ts). They now name it in the past tense. The two
in-workflow analogies (the typecheck:test ratchet and PG_TEST_FLOOR, which is
explicitly the inverse convention) no longer say "the job above".

In specs/470-dev-platform-plugin/, the live Baseline **N** and "run the ratchet"
rows are replaced by a short closing note in README.md, acceptance.md, plan.md
and implementation.md. Two facts are deliberately kept because they outlive the
guard: it counted identifiers, not behaviour (zero was never sufficient for done —
§2/§3 of acceptance.md cover the rest, and neither is automated), and
services/githubAppJwt.ts stays in core, since moving it would recreate the
reverse dependency across a repo boundary. The checklist's baseline-raise log is
marked historical rather than deleted — it is the record of how the count moved.
implementation.md gains a C14 row. docs/CHANGELOG.md gets a ### Removed entry.

Verification

• middleware: npm run build, npm run typecheck, npm run lint, and
  npm run typecheck:test (the test-tree ratchet) — all exit 0
• web-ui: npm run lint — exit 0
• actionlint .github/workflows/ci.yml — clean; the four remaining jobs
  (middleware, web-ui, schema, audit) still map exactly onto the five required
  checks. Pre-existing shellcheck findings in auto-release.yml, desktop-apps.yml
  and release.yml are untouched by this PR.
• git grep -n 'check-core-decoupling\|decoupling-baseline\|decoupling ratchet' returns
  only the historical notes written here plus the existing C13 changelog entry. Greps
  for EXTRACTION_COMPLETE, TOTAL 0 and decoupling.txt return nothing.

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