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/skill-audit/references/body-discipline.md

@@ -0,0 +1,88 @@
+---
+source_keys:
+  - agentskills-spec
+  - agentskills-best-practices
+---
+
+# Body Discipline Reference
+
+Source: agentskills.io — skill-authoring
+
+## The core test
+
+For every sentence in the body, ask: **"Would the agent get this wrong without this instruction?"**
+
+If no — cut it. The agent already knows it from general training. Adding it wastes tokens and dilutes the signal of what matters.
+
+## What belongs in the body
+
+Include content the agent lacks:
+- Project-specific conventions and domain procedures it cannot infer
+- Non-obvious edge cases and environment-specific gotchas
+- The specific tools or sequences to use (not the full range of options)
+- One default per decision point with one escape hatch
+
+Do not include:
+- Concepts the agent already knows (what JSON is, how HTTP works, what a CSV is)
+- Exhaustive option lists — pick a default; the agent doesn't benefit from choosing
+- Steps the agent handles independently — over-specifying leads to unproductive paths
+- Restatements of the description — it's already in context
+
+## Calibrating control
+
+**Be prescriptive** when operations are fragile, consistency matters, or a specific sequence must be followed:
+```markdown
+Run exactly:
+\`\`\`bash
+python scripts/migrate.py --verify --backup
+\`\`\`
+Do not modify the command or add additional flags.
+```
+
+**Give freedom** when multiple approaches are valid. Explaining *why* outperforms rigid directives — agents make better decisions when they understand the purpose.
+
+## Defaults not menus
+
+Never present a list of equivalent options — pick one and mention the alternative briefly:
+```markdown
+# Too many options
+Use pypdf, pdfplumber, PyMuPDF, or pdf2image...
+
+# Default with escape hatch
+Use pdfplumber for text extraction. For scanned PDFs requiring OCR, use pdf2image instead.
+```
+
+## Gotchas sections
+
+Highest value content — environment-specific facts that defy reasonable assumptions. Place near the top of the body so the agent reads them before encountering the situation.
+
+```markdown
+## Gotchas
+- The `users` table uses soft deletes. Always include `WHERE deleted_at IS NULL`.
+- User ID is `user_id` in the database, `uid` in auth, `accountId` in billing. Same value.
+```
+
+Each entry must be a specific, surprising fact — not a general tip or reminder.
+
+## Progressive disclosure
+
+Keep `SKILL.md` under 500 lines. When more content is needed, move it to `references/` and load conditionally:
+
+```markdown
+If the API returns a non-200 status, read `references/api-errors.md`.
+```
+
+"If X, read Y" is more useful than "see references/ for details." The agent loads on demand rather than up front.
+
+## Auditing guidance
+
+Flag as FAIL if:
+- A sentence answers "no" to the core test (would agent get this wrong without it?) — it is padding
+- Decision points present a menu of options with no default
+- Instructions repeat content already in the description
+- Prescriptive sequences are used where flexibility is fine, or vice versa
+
+Flag as SUGGESTION if:
+- A rationale is missing from an include/exclude rule (present but unexplained)
+- Gotchas are correct but placed late in the body rather than near the top
+- A conditional reference trigger is vague ("see references/") rather than specific ("If X, read Y")