fix(kyberforge): bridge apm content to Claude Code's flat plugin discovery

Claude Code's (and Copilot's) native plugin installer has zero awareness of
.apm/ nesting -- it convention-scans only flat skills/, agents/, commands/,
hooks.json at each plugin's root. Confirmed via strings on the installed
claude binary and live installs of git@holocron/gitea@holocron/kyberforge@
holocron, all reporting Skills(0) Agents(0) Hooks(0) post ADR-0015's apm
conversion. Root cause (apm_cli/core/plugin_manifest.py): apm's plugin.json
compiler deliberately strips skills/agents/commands keys, assuming the host
already auto-discovers those convention directories -- it has no model of
.apm/ being host-visible at all. Separately, apm's own bundle exporter
(apm_cli/bundle/plugin_exporter.py, behind `apm pack --format plugin`)
implements the correct .apm/ -> flat mapping, but only ever targeted
build/<name>-<version>/, a path nothing in marketplace.json's source: points
at.

scripts/sync-plugin-content.sh wraps that bundle exporter and copies its
agents/, skills/, commands/, instructions/, extensions/, and merged
hooks.json back into each plugin's own root as a second tracked
compiled-output category -- same governance status as
.claude-plugin/plugin.json: generated from .apm/, never hand-edited. tests/
subdirectories are excluded from the mirror (dev fixtures, not host-visible
runtime content; several hardcode a relative repo-root walk-up sized for the
.apm/-nested depth, which breaks when duplicated one level shallower).
Applied for real across all 6 plugins and verified two ways: `claude plugin
validate --strict` passes on every real plugin directory, and a live
`claude --plugin-dir <path> -p "list skills/agents"` behavioral test
confirms content is now actually discovered.

Also, from the same issue #90 review round:
- scripts/check-manifests.sh pointed at each plugin's root-level plugin.json
  (checking skills/hooks/mcpServers/agents pointer fields) -- that file was a
  stale near-duplicate of .claude-plugin/plugin.json nothing else read or
  wrote, now deleted across all 6 plugins. check-manifests.sh is rewritten to
  validate .claude-plugin/plugin.json instead, and drops the pointer-field
  checks entirely (nothing to check -- those fields are correctly absent by
  design). Content-presence drift is now check-plugin-content-sync's job, a
  new pre-push hook wired in .pre-commit-config.yaml.

docs/adr/0017 records the root cause and decision in full, including two
rejected alternatives (patching plugin.json's path fields directly -- apm's
compiler strips them on every run; pointing marketplace.json at apm pack's
build/ output -- a version-suffixed non-source directory nothing can install
from without an extra build step). ADR-0015 and CONTEXT.md are updated to
point at it.

Refs: #90

plugins/kyberforge/skills/apm-workflow/references/audit.md

@@ -0,0 +1,55 @@
+---
+topic: audit
+source_keys:
+  - context7-microsoft-apm
+  - context7-websites-code-claude
+  - claude-code-plugins-docs
+---
+
+## `apm audit`
+
+```bash
+apm audit                  # local: scan deployed files for hidden Unicode
+apm audit --ci              # CI gate: lockfile consistency + drift replay + policy
+apm audit --file <path>     # standalone: scan an arbitrary file
+```
+
+Exit code `0` on success, `1` on any violation — composes as a normal CI gate step. It does not replace general lint/test/security-scan CI steps, it sits alongside them.
+
+## Policy checks
+
+`apm audit --ci` auto-discovers an org policy from the git remote if `--policy`/`--policy-source` isn't given explicitly; `--no-policy` skips policy discovery for a single invocation.
+
+## Marketplace ref validation
+
+Separate from `apm audit`: `apm marketplace check` validates that every package reference declared in a marketplace's `apm.yml` actually resolves (correct path/ref, manifest present) — run before `apm pack`/publish, to catch a typo'd local path or stale pinned tag before it ships.
+
+## CI integration example (GitHub Actions)
+
+```yaml
+jobs:
+  apm-audit:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      security-events: write
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with: { python-version: "3.12" }
+      - run: pip install apm-cli==X.Y.Z  # pin to the version standardized on
+      - run: apm install
+      - run: apm audit --ci -f sarif --output apm-audit.sarif
+      - uses: github/codeql-action/upload-sarif@v3
+        with: { sarif_file: apm-audit.sarif }
+```
+
+`-f sarif --output <file>` emits SARIF for GitHub Code Scanning's inline PR annotations.
+
+## Frozen installs
+
+`apm install --frozen` fails instead of silently re-resolving if the lockfile is out of date — the CI equivalent of `npm ci` vs `npm install`. Use in any CI job that must not be allowed to drift the lockfile.
+
+## Claude Code validation is a separate terminal check
+
+For packages compiling to the `claude` target, also run `claude plugin validate [--strict]` against the compiled output as a terminal check. `apm audit`/`apm audit --ci` do not check Claude Code-marketplace-specific schema rules (reserved prefixes, the `agents/` stray-file behavior — see `references/compile.md` — etc.), so they don't substitute for it.