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-author/references/scripts.md

@@ -0,0 +1,89 @@
+---
+source_keys:
+  - agentskills-using-scripts
+---
+
+# Scripts Reference
+
+## Package runners (no install required)
+
+When an existing package does what you need, use a runner directly in SKILL.md without writing a script file.
+
+| Runner | Language | Notes |
+|--------|----------|-------|
+| `uvx package@version` | Python | Recommended. Aggressive caching via uv. |
+| `pipx run 'package==version'` | Python | Broader OS availability. |
+| `npx package@version` | Node.js | Ships with npm/Node.js. |
+| `bunx package@version` | Node.js | Bun environments only. |
+| `deno run npm:package@version` | TypeScript | Requires permission flags (`--allow-read`, etc.). |
+| `go run golang.org/x/...@version` | Go | Built into Go toolchain. |
+
+Always pin versions. Never use `pip install` or `npm install -g` at runtime — they are not idempotent and pollute the environment.
+
+## Inline dependency patterns
+
+Use these when the script requires packages but should remain a single portable file.
+
+**Python (PEP 723 + uv):**
+```python
+# /// script
+# dependencies = [
+#   "beautifulsoup4>=4.12,<5",
+# ]
+# requires-python = ">=3.12"
+# ///
+from bs4 import BeautifulSoup
+```
+```bash
+uv run scripts/extract.py
+```
+
+**TypeScript (Deno):**
+```typescript
+#!/usr/bin/env -S deno run
+import * as cheerio from "npm:cheerio@1.0.0";
+```
+```bash
+deno run scripts/extract.ts
+```
+
+**TypeScript (Bun):**
+```typescript
+#!/usr/bin/env bun
+import * as cheerio from "cheerio@1.0.0";
+```
+```bash
+bun run scripts/extract.ts
+```
+
+**Ruby (bundler/inline):**
+```ruby
+require 'bundler/inline'
+gemfile do
+  source 'https://rubygems.org'
+  gem 'nokogiri', '~> 1.16'
+end
+```
+```bash
+ruby scripts/extract.rb
+```
+
+## Script contract
+
+Rules for all agentic scripts:
+
+- **Self-contained** — bundle dependencies inline so the agent can run the script with a single command; do not require a separate install step
+- **Structured output** — data (JSON, CSV) to stdout; diagnostics and progress to stderr
+- **Idempotent** — "create if not exists"; agents may retry on failure
+- **Input constraints** — validate inputs early; reject unknown or ambiguous values with a clear error rather than proceeding silently
+- **Meaningful exit codes** — `0` success, non-zero failure; document in `--help`
+- **Dry-run support** — add `--dry-run` for destructive operations; pair with `--confirm`/`--force` for operations that can't be undone
+- **Error messages** — on failure, state what went wrong, what was expected, and what to try; vague errors leave agents unable to self-correct
+
+## --help output
+
+Keep `--help` output concise — it enters the agent's context window. Include: usage line, one-line description, options with defaults, exit codes. Omit prose explanations.
+
+## Output size
+
+Many harnesses truncate tool output beyond 10–30K characters. Default to a summary or a reasonable output limit. For scripts that can produce large output: support `--offset N` for pagination, or use `--output FILE` to write to disk and keep stdout clean.