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/0015-apm-replaces-plugin-marketplace-authoring.md

@@ -5,6 +5,12 @@ their authoring source; `.claude-plugin/marketplace.json` and every plugin's `pl
 `apm pack`-compiled output. **Supersedes ADR-0001** ("Skills are distributed via plugins... each
 plugin contains its own `skills/` directory") — in effect.
 
+**Correction (2026-09-20): the present tense above has expired for `plugin.json`.** ADR-0024 made
+apm the only supported install path and deleted per-plugin `plugin.json` with the native install
+support that needed it. No plugin carries one at `HEAD` — `git ls-files | grep -c 'plugin\.json'`
+returns 0 — so `.claude-plugin/marketplace.json` is the only `apm pack`-compiled output left. Read
+the Status line as the state at execution, 2026-08-12.
+
 This repo replaces its hand-maintained Claude Code plugin/marketplace authoring model
 (`.claude-plugin/marketplace.json` + per-plugin `plugin.json`) with Microsoft APM (`apm.yml` +
 `.apm/`) as the authoring source of truth — an outright replacement of the authoring layer, not an
@@ -180,7 +186,11 @@ correction) sorted what they document into three buckets:
   `git ls-remote`, which is why two pre-push hooks needed the network (see `AGENTS.md`).
   **Superseded 2026-09-13:** the `mattpocock-skills` entry has been removed from root `apm.yml`
   entirely, along with the `codex` marketplace output profile. No pre-push hook needs the network
-  any longer.
+  any longer — **once `apm install` has populated `apm_modules/`**. The guarantee is a property of a
+  populated install, not of the hook set: on a fresh clone `apm-audit-ci`'s `deployed-files-present`
+  fails outright, and its `drift` and `config-consistency` install-replays have no cache to replay
+  from and clone from the holocron remote (`README.md:89`; `docs/spec/gates.md`, "Pushing without a
+  network").
 - **Caveat on "Status: executed" above:** issue #90's own execution comment flagged, before merge,
   that Claude Code's ability to actually load content out of `.apm/` was unverified — that caveat
   turned out to be a real defect, not a formality: the native installer has zero awareness of