feat(plugin): command metadata, scoped skills, local-tier support, layered hooks, Stop audit

Wave 3 - adoption hardening. Patterns adapted (in original prose, with
attribution) from MIT-licensed shanraisshan/claude-code-best-practice.

Commands (command/enhance-claude-md.md, command/sync-claude-md.md):
- Add allowed-tools / disallowedTools / argument-hint / when_to_use so the
  commands auto-suggest in the slash menu and avoid permission prompts.
- disallowedTools blocks WebFetch + WebSearch on both commands.
- Drop the previous broken hooks block (array-of-{matcher, commands} shape
  did not match canonical schema; was never firing).

Skills:
- skill/karpathy-guidelines/SKILL.md: paths: glob over 23 code-file
  extensions, so the guardrails auto-load only when editing source, not
  markdown or data.
- skill/SKILL.md: model: haiku, effort: medium, paths: scoped to CLAUDE.md
  + AGENTS.md + .claude/rules/*.md so validator/generator passes run
  cheaply without changing the user-facing model.

CLAUDE.local.md personal tier:
- skill/validator.py BestPracticesValidator now accepts filename=; any
  *.local.md basename waives the 150-line cap.
- hooks/validate-claude-md.py reads the exempt suffix from hooks-config.
- .gitignore covers CLAUDE.local.md, **/CLAUDE.local.md,
  .claude/settings.local.json, hooks/hooks-config.local.json.

Layered hook config:
- hooks/hooks-config.json: committed defaults
  (validateClaudeMd.enabled/maxLines/exemptFilenameSuffix/exitCodeOnViolation,
  stopAuditLine.enabled).
- hooks/validate-claude-md.py merges hooks-config.json +
  hooks-config.local.json key-by-key; honours enabled=false (silent
  exit 0), configurable cap, configurable exit code.

Stop audit hook:
- hooks/audit-claude-md.py walks the project tree, prints one stderr
  line: total tracked / OVER cap / near cap (>=80%). Respects
  stopAuditLine.enabled from config.
- hooks/hooks.json registers Stop event with matcher "".

Guardian fail-closed contract:
- agent/claude-md-guardian.md Safety & Validation section now explicitly
  requires Skill-tool invocation (no inline paraphrase of SKILL.md),
  abort on missing validated output, never auto-commit, and respect
  local hook config.

Verified (8/8 smoke tests):
- Both commands parse with new fields and no broken hooks block.
- karpathy paths: 23 globs, includes .py/.ts/.go/.rs.
- skill model=haiku effort=medium with CLAUDE.md path scope.
- Validator: *.local.md (300 lines) -> pass; CLAUDE.md (300) -> fail;
  legacy ctor without filename -> default behavior preserved.
- hooks-config.json valid; validateClaudeMd.enabled=true, maxLines=150.
- Hook validator: default rc=2 on bloated, rc=0 when local override
  disables it, rc=0 on *.local.md (exempt).
- Stop hook entry present; audit script: rc=0 with "5 CLAUDE.md tracked".
- Regression: large-fullstack root still 52 lines with chain imports.

hooks/validate-claude-md.py

@@ -17,7 +17,32 @@ import json
 import os
 import sys
 
-MAX_LINES = 150
+DEFAULT_MAX_LINES = 150
+DEFAULT_EXEMPT_SUFFIX = ".local.md"
+DEFAULT_VIOLATION_RC = 2
+
+
+def _load_config() -> dict:
+    """Merge ``hooks-config.json`` and optional ``hooks-config.local.json``.
+
+    Local file overrides the shared one key-by-key inside ``validateClaudeMd``.
+    Missing files are silently ignored — the script falls back to defaults.
+    """
+    here = os.path.dirname(os.path.abspath(__file__))
+    shared = os.path.join(here, "hooks-config.json")
+    local = os.path.join(here, "hooks-config.local.json")
+    cfg: dict = {}
+    for path in (shared, local):
+        if not os.path.exists(path):
+            continue
+        try:
+            with open(path, encoding="utf-8") as fh:
+                data = json.load(fh)
+        except (OSError, json.JSONDecodeError):
+            continue
+        validate_block = data.get("validateClaudeMd") or {}
+        cfg.update(validate_block)
+    return cfg
 
 
 def _candidate_paths(payload: dict) -> list[str]:
@@ -42,9 +67,13 @@ def _candidate_paths(payload: dict) -> list[str]:
     return paths
 
 
-def _is_claude_md(path: str) -> bool:
+def _is_claude_md(path: str, exempt_suffix: str) -> bool:
     base = os.path.basename(path)
-    return base == "CLAUDE.md" or base.endswith(".claude/rules") or "/.claude/rules/" in path
+    # Personal-tier overrides (CLAUDE.local.md and any matching suffix) are
+    # exempt from the cap — they live outside the chained team-shared tree.
+    if base.endswith(exempt_suffix):
+        return False
+    return base == "CLAUDE.md" or "/.claude/rules/" in path
 
 
 def main() -> int:
@@ -59,16 +88,23 @@ def main() -> int:
     except json.JSONDecodeError:
         return 0
 
+    cfg = _load_config()
+    if cfg.get("enabled") is False:
+        return 0
+    max_lines = int(cfg.get("maxLines", DEFAULT_MAX_LINES))
+    exempt_suffix = str(cfg.get("exemptFilenameSuffix", DEFAULT_EXEMPT_SUFFIX))
+    violation_rc = int(cfg.get("exitCodeOnViolation", DEFAULT_VIOLATION_RC))
+
     violations: list[tuple[str, int]] = []
     for path in _candidate_paths(payload):
-        if not _is_claude_md(path) or not os.path.exists(path):
+        if not _is_claude_md(path, exempt_suffix) or not os.path.exists(path):
             continue
         try:
             with open(path, encoding="utf-8") as fh:
                 line_count = sum(1 for _ in fh)
         except OSError:
             continue
-        if line_count > MAX_LINES:
+        if line_count > max_lines:
             violations.append((path, line_count))
 
     if not violations:
@@ -76,11 +112,11 @@ def main() -> int:
 
     for path, line_count in violations:
         print(
-            f"ClaudeForge: {path} is {line_count} lines (cap is {MAX_LINES}). "
+            f"ClaudeForge: {path} is {line_count} lines (cap is {max_lines}). "
             "Run /sync-claude-md to split into chained sub-files.",
             file=sys.stderr,
         )
-    return 2
+    return violation_rc
 
 
 if __name__ == "__main__":