docs(adr): correct the records the branch left describing deleted things

Seven ADRs described code that no longer exists or behaviour the gates do
not have. Where the wrong text came from main it carries a dated
correction; where this branch introduced it, it is fixed in place, because
main never published it and there is no record to preserve.

Fixed in place, branch-introduced:

- ADR-0021's 2026-09-14 correction asserted apm audit --ci "was never a
  drift gate at all". It is one: it replays the install and diffs. The
  claim contradicted this branch's own AGENTS.md and gates.md.
- ADR-0015 said unconditionally that no pre-push hook needs the network.
  The guarantee holds only once apm install has populated apm_modules/.
- ADR-0014's 2026-09-16 correction said restoring .pre-commit-hooks.yaml
  would ship a hook that fails for every consumer, because their checkout
  has no lib-boundary-resolver.sh. pre-commit clones the whole hook repo
  and skill-size-check.sh resolves the library from BASH_SOURCE, so the
  hook would work.
- ADR-0019's "twelve hooks pass under unshare -rn" matched neither HEAD
  (8) nor main (14), and stated the offline guarantee unconditionally.

Corrected, inherited from main:

- ADR-0022 and ADR-0013 named skill-frontmatter's pre-commit hook as the
  enforcer of mandatory metadata.version. That hook was deleted on this
  branch; the check lives in skill-size-check.sh.
- ADR-0022 enumerated the tip rule's carve-outs as a closed list and
  described a single merge-base. The gate also exempts a tree-identical
  skill and intersects every base from merge-base --all, and emits a third
  failure form. 8cfd54f said the documented behaviour did not change; it
  did. The gate is correct and is unchanged -- the record was not.
- ADR-0020's Decision still routed description overflow to README.md, its
  ADR-0025 amendment pointed the mirrored constants at validate.sh, which
  holds none, and its Enforcement table still named the two deleted
  validate.sh paths.
- ADR-0015's Status claimed every plugin's plugin.json is pack output;
  none exist.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NwD8Egs5r4ndqeFLmhusX2

docs/adr/0020-skill-description-and-body-context-contract.md

@@ -21,9 +21,12 @@ SHARED BOUNDARY RESOLVER` markers, and one plugin copy — extracted out of the
 both. `validate-provenance.sh` is not a third reader: it sources `lib-contributing-files.sh` and one
 of `lib-provenance-skill.sh`/`lib-provenance-agent.sh`, and never touches the resolver at all. The
 Enforcement table's "constants mirrored in `skill-audit/scripts/validate.sh` and
-`agent-audit/scripts/validate.sh`" is one path now, `factory-audit/scripts/validate.sh`, which
-auto-detects the artifact type; the skills/agents columns are unaffected, since the merged validator
-applies the body tiers on the skill path only. The two copies must still stay byte-identical — a
+`agent-audit/scripts/validate.sh`" now means `factory-audit/scripts/lib-checks-skill.sh:313-316`
+(all four constants) and `lib-checks-agent.sh:164-165` (the two description ones). It does **not**
+mean `factory-audit/scripts/validate.sh`, which holds none of them: `validate.sh` auto-detects the
+artifact type and sources the matching check suite (`validate.sh:231-233`, `:244-246`). The
+skills/agents columns are unaffected — only the skill suite carries the body tiers. The two copies
+must still stay byte-identical — a
 plugin script cannot source the root one, which is why a second copy exists at all. Read every
 "three" below as the count at the time of writing.
 
@@ -116,6 +119,12 @@ clause**, and a **boundary clause**. Capability enumeration, output-format detai
 ("composes X rather than duplicating Y"), and implementation detail move to the body or to
 `README.md`.
 
+**Correction (2026-09-20): not `README.md`.** The canonical destination for description overflow is
+"the body or a `references/` file" (`plugins/kyberforge/.apm/skills/skill-author/references/contract.md:35`).
+A skill-root `README.md` is no longer somewhere overflow can go: all 39 of them were deleted, and
+`factory-audit/references/skill-file-structure.md:23` now FAILs a non-spec file at the skill root,
+which a `README.md` is. Read every "or to `README.md`" below as "or to a `references/` file".
+
 - **250 characters SUGGESTION, 400 FAIL.** The agentskills.io 1,024-character limit remains as an
   unchanged spec backstop. The SUGGESTION tier is what moves the average; the FAIL tier only stops
   outliers.
@@ -284,8 +293,8 @@ which tier each rule is in, because the failure this ADR is most exposed to is a
 
 | Check | Applies to | Tier | Home |
 |---|---|---|---|
-| description characters (250 SUGGESTION † / 400 FAIL) | skills, agents | deterministic | `scripts/skill-size-check.sh`; constants mirrored in `skill-audit/scripts/validate.sh` and `agent-audit/scripts/validate.sh` |
-| body-only words (600 SUGGESTION / 900 FAIL) | skills | deterministic | `skill-size-check.sh`, `skill-audit/scripts/validate.sh` (now `factory-audit/scripts/validate.sh`, see ADR-0025) |
+| description characters (250 SUGGESTION † / 400 FAIL) | skills, agents | deterministic | `scripts/skill-size-check.sh`; constants mirrored in `skill-audit/scripts/validate.sh` and `agent-audit/scripts/validate.sh` (now `factory-audit/scripts/lib-checks-skill.sh:313-314` and `lib-checks-agent.sh:164-165`, see the ADR-0025 amendment — **not** `factory-audit/scripts/validate.sh`, which holds no constants) |
+| body-only words (600 SUGGESTION / 900 FAIL) | skills | deterministic | `skill-size-check.sh`, `skill-audit/scripts/validate.sh` (now `factory-audit/scripts/lib-checks-skill.sh:315-316`, see the ADR-0025 amendment) |
 | description present and non-empty (ERROR) | skills, agents | deterministic | same |
 | boundary target resolves to a real skill or agent — **three** verdicts, not two (ERROR when written in route notation — `/name`, or any arrow form; or when a *terminal* bare name's own sentence names another target that resolves. SUGGESTION otherwise. INFO, "DID NOT RUN", exit 0, when no skill universe could be determined for the path at all — no authoring root above it, no apm package root, no declared apm dependencies, no deployed `.claude/` or `.agents/` tree: the targets are named and left unchecked) | skills, agents | deterministic | same |
 | boundary clause absent — `absent` (SUGGESTION) † | skills, agents | deterministic | same |