MANIFEST.md inventory drifts silently: generate it from the corpus instead of hand-maintaining it

[mbeacom]

What happened

While ratifying the pending ADR queue (#129), MANIFEST.md was found publishing contradictory governance state. It was not slightly stale — it had drifted independently for six records:

MANIFEST claimed	Actual
19 records, ids 0001–0019	25 records, ids 0001–0025
13 accepted, 6 proposed	23 accepted, 1 proposed, 1 superseded
0003, 0006–0009 proposed	all five accepted
"Six records remain proposed"	one does (0005)

It was corrected by hand in fe4363a. That fixes the symptom, not the cause: the inventory is a hand-maintained mirror of state the corpus already defines, so it can drift silently again the moment a record is added.

Why a check is only half a fix

A guard that fails on divergence still leaves a human to hand-edit the table — which is exactly how it drifted. This repo already has the better pattern, twice:

• Generate, then assert no diff — bun run schema:emit && git diff --exit-code schema/adr.schema.json in clean-clone-builds. Same shape for the committed Action bundle (git diff --exit-code packages/ci/dist).
• Read-only CLI, redirected — "site:queue": "adr queue --format json > site/public/queue.json".

The data already exists

No new CLI surface is needed. adr graph --format json already emits exactly what the inventory needs:

{ "nodes": [ { "id": "0001", "title": "...", "status": "accepted" } ] }

So this is a renderer plus a gate, not a feature:

1. scripts/emit-manifest.ts renders the inventory block and the counts from adr graph --format json, writing between stable markers in MANIFEST.md.
2. bun run emit:manifest && git diff --exit-code MANIFEST.md joins the existing guards in clean-clone-builds (already a required check, so it cannot reach main stale).

This keeps it a repo-local guard, consistent with the reasoning scripts/check-doc-cli-versions.ts states in its own docblock for living in scripts/ rather than becoming CLI surface. The general question — whether adopters get a supported way to keep their own docs in lockstep — is scoped separately.

One wrinkle worth deciding

MANIFEST's table uses short hand-written labels (git-native markdown records) rather than record titles (Record architecture decisions as versioned markdown in git). Either the generated table switches to real titles (simpler, self-maintaining, slightly more verbose), or the script keeps a label map that itself needs a completeness check. Prefer real titles unless the width is genuinely a problem.

Done when

• The MANIFEST inventory and counts are generated, not hand-written
• A divergence gate runs in clean-clone-builds
• Observed failing against a deliberately stale MANIFEST before it counts as coverage (ADR-0016)
• The "Known-open, deliberately" prose stays hand-written — it is judgment, not derived state

Found in #129. Broader scoping in the companion issue.