docs(claude-md): dogfood /sync-claude-md on root CLAUDE.md

Splits the 518-line root CLAUDE.md into a 70-line root plus four chained
sub-files (skill/, command/, agent/, docs/), all under the 150-line cap,
and prunes stale references uncovered by the audit.

- CLAUDE.md (518 -> 70): project overview, navigation with @-imports,
  behavioural guidelines summary, naming reference, license link
- skill/CLAUDE.md (85): component flow, Python module architecture,
  modifying modules, adding templates, tech-stack detection, quality
  scoring, karpathy skill
- command/CLAUDE.md (38): slash command development, top-level .md install
  layout, skill <-> command integration
- agent/CLAUDE.md (70): guardian frontmatter, hook responsibilities,
  skill <-> agent integration, git triggers
- docs/CLAUDE.md (109): install verification, smoke test, manual e2e
  tests, common operations, release process

Stale content removed:
- 'Dual Directory Structure' section (claude-md-enhancer/ legacy dir
  does not exist on disk)
- '20-300 lines' / '300-line cap' references rewritten to 150
- '~/.claude/commands/enhance-claude-md/' bundle paths rewritten to
  top-level '.md' files (matching the new installer layout)
- 'Three integrated components' updated to five
- 'Current Version: 2.0.0' updated to 2.1.0
- '6 examples' in sample_input.json claim corrected (file has 1 scenario)

Each sub-file opens with a markdown back-link and @../CLAUDE.md import;
root contains @-imports for all four sub-files. Validator passes (status
pass) for every file.

skill/CLAUDE.md

@@ -0,0 +1,85 @@
+> Parent context: see the root [CLAUDE.md](../CLAUDE.md) for project-wide guidelines and behavioural rules.
+> Chained import: `@../CLAUDE.md`
+
+# Skill Development
+
+Guidelines for the `claudeforge-skill` Python modules and the `karpathy-guidelines` skill.
+
+## Component Interaction Flow
+
+```
+User Project
+    ↓
+/enhance-claude-md (Slash Command)  →  Explore subagent (deep scan)
+    ↓
+[Discovery] → [Analysis] → [Task]
+    ↓
+claude-md-guardian (Agent) OR Direct Skill Invocation
+    ↓
+claudeforge-skill (Python Modules)
+    ↓
+workflow.py → analyzer.py → validator.py → template_selector.py → generator.py
+    ↓
+CLAUDE.md ≤ 150 lines, chained via `@path` imports
+```
+
+## Python Module Architecture
+
+Five modules live under `skill/`:
+
+- **`workflow.py`** — `InitializationWorkflow`: orchestrates interactive setup, detects project type / tech stack / team size / phase / workflows, returns a context dict.
+- **`analyzer.py`** — `CLAUDEMDAnalyzer`: analyses existing files; quality scoring (0–100) across length, completeness, formatting, specificity, modularity.
+- **`validator.py`** — `BestPracticesValidator`: checks file length (hard cap 150, warning at 120), required sections, formatting, anti-patterns.
+- **`template_selector.py`** — `TemplateSelector`: maps project type + team size to a template; all team-size targets are ≤ 150 lines.
+- **`generator.py`** — `ContentGenerator`: writes root + context files, emits `@path` chain imports, prepends sub-file back-links, idempotent `merge_with_existing`.
+
+## Required Output Sections
+
+Every generated CLAUDE.md must contain:
+
+- Project structure (ASCII tree, for projects that need it)
+- Setup & installation
+- Architecture (for non-trivial projects)
+- `## Behavioral Guidelines` (Karpathy summary — inserted automatically)
+- Cross-check against reference examples in `skill/examples/`
+
+## Modifying Python Modules
+
+1. Edit files in `skill/`.
+2. Run the smoke test (see `docs/CLAUDE.md` → Testing & Validation).
+3. Re-install for live testing: `./install.sh` (project-level scope).
+4. Test slash command: `/enhance-claude-md`.
+5. Validate output against `skill/examples/`.
+6. Update `CHANGELOG.md`.
+
+## Adding Reference Templates
+
+1. Add a new file under `skill/examples/`.
+2. Follow the native format (project structure, setup, architecture, tech guidelines).
+3. Update `skill/examples/README.md`.
+4. Teach `template_selector.py` how to detect the new template.
+5. Add a scenario to `skill/sample_input.json`.
+
+## Quality Scoring (analyzer.py)
+
+`calculate_quality_score()` breakdown:
+
+- length_appropriateness: 25 pts (50–150 lines ideal; the 150-line hard cap is enforced here)
+- section_completeness: 25 pts (required sections present)
+- formatting_quality: 20 pts (markdown, heading hierarchy, code blocks)
+- content_specificity: 15 pts (project-specific, not generic)
+- modular_organization: 15 pts (chained sub-files when needed)
+
+## Tech Stack Detection
+
+`skill/workflow.py` → `_detect_tech_stack()` reads these signals:
+
+- **Frontend** — React/Vue/Angular via `package.json`; Angular via `angular.json`; TypeScript via `tsconfig.json`.
+- **Backend** — Node (`package.json`), Python (`requirements.txt` / `pyproject.toml` / `setup.py`), Go (`go.mod`), Java (`pom.xml` / `build.gradle`), Rust (`Cargo.toml`).
+- **Database** — Postgres (`pg` / `psycopg2`), MongoDB (`mongoose` / `pymongo`), Redis (`redis` / `ioredis`).
+
+Add new detectors there, not in the template selector.
+
+## Karpathy Guidelines Skill
+
+`skill/karpathy-guidelines/SKILL.md` is the standalone skill installed at `~/.claude/skills/karpathy-guidelines/`. Adapted with attribution from the MIT-licensed [forrestchang/andrej-karpathy-skills](https://github.com/forrestchang/andrej-karpathy-skills) repo. The four principles are inserted automatically into every generated CLAUDE.md via `template_selector._generate_karpathy_guidelines()` and `generator._generate_karpathy_guidelines()`. Do not strip the embedded section during enhancement.