feat: add CLAUDE.md project context

- Repository purpose and structure
- Key files reference
- Version management commands
- Documentation conventions
- Quick lookup workflow for answering questions

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,94 @@
+# Claude Code Ultimate Guide - Project Context
+
+## Purpose
+
+This repository is the **comprehensive documentation for Claude Code** (Anthropic's CLI tool). It teaches users how to use Claude Code effectively through guides, examples, and templates.
+
+**Meta-note**: This repo documents Claude Code, so its own configuration should be exemplary.
+
+## Repository Structure
+
+```
+guide/                    # Core documentation
+├── ultimate-guide.md     # Main guide (~9500 lines, the reference)
+├── cheatsheet.md         # 1-page printable summary
+├── architecture.md       # How Claude Code works internally
+├── methodologies.md      # TDD, SDD, BDD workflows
+├── data-privacy.md       # What data is sent to Anthropic
+├── security-hardening.md # Security best practices
+└── workflows/            # Step-by-step workflow guides
+
+examples/                 # Production-ready templates
+├── agents/               # Custom agent templates
+├── commands/             # Slash command templates
+├── hooks/                # Event hook examples (bash/powershell)
+├── skills/               # Skill module templates
+└── scripts/              # Utility scripts (audit, health check)
+
+machine-readable/         # For LLM consumption
+├── reference.yaml        # Condensed index (~2K tokens)
+└── llms.txt              # AI indexation file
+
+tools/                    # Interactive utilities
+├── audit-prompt.md       # Setup audit prompt
+└── onboarding-prompt.md  # Personalized learning prompt
+```
+
+## Key Files
+
+| File | Purpose |
+|------|---------|
+| `VERSION` | Single source of truth for version (currently 3.6.0) |
+| `guide/ultimate-guide.md` | The main reference (search here first) |
+| `guide/cheatsheet.md` | Quick reference for daily use |
+| `machine-readable/reference.yaml` | LLM-optimized index with line numbers |
+| `CHANGELOG.md` | All changes with detailed descriptions |
+
+## Commands
+
+### Version Management
+```bash
+# Check version consistency across all docs
+./scripts/sync-version.sh --check
+
+# Fix version mismatches (updates from VERSION file)
+./scripts/sync-version.sh
+
+# Bump version
+echo "3.7.0" > VERSION && ./scripts/sync-version.sh
+```
+
+### Before Committing
+```bash
+# Verify versions are synchronized
+./scripts/sync-version.sh --check
+```
+
+## Conventions
+
+### Documentation Style
+- **Accuracy over marketing**: No invented percentages or unverified claims
+- **Practical examples**: Every concept has a concrete example
+- **Source attribution**: Credit community contributions with links
+- **Version alignment**: All version numbers must match `VERSION` file
+
+### File Organization
+- New guides → `guide/`
+- New templates → `examples/{agents,commands,hooks,skills}/`
+- Navigation updates → Update both `README.md` and `guide/README.md`
+
+### Versioning
+- `VERSION` file is the single source of truth
+- Run `./scripts/sync-version.sh` after changing version
+- Files that contain version: README.md, cheatsheet.md, ultimate-guide.md, reference.yaml
+
+## Current Focus
+
+Check `IDEAS.md` for planned improvements and `CHANGELOG.md [Unreleased]` for work in progress.
+
+## Quick Lookups
+
+For answering questions about Claude Code:
+1. Search `machine-readable/reference.yaml` first (has line numbers to full guide)
+2. Use those line numbers to read relevant sections from `guide/ultimate-guide.md`
+3. Check `examples/` for ready-to-use templates