Add CLAUDE.md, README, and development tooling docs

- CLAUDE.md: project context for Claude Code sessions
- README.md: human-facing project intro, structure, getting started
- docs/tooling.md: cmux, Claude Code, Crit, and OpenSpec workflow

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

README.md

@@ -0,0 +1,94 @@
+# trails.cool
+
+Collaborative route planning and federated activity sharing for outdoor
+enthusiasts.
+
+**Planner** — Plan routes together in real-time. Share a link, invite friends,
+edit waypoints collaboratively. Powered by [BRouter](https://github.com/abrensch/brouter)
+for intelligent routing with elevation awareness.
+
+**Journal** — Track your adventures. Import activities from Garmin, Strava, or
+Wahoo. Share routes and rides with friends. Self-host your own instance and
+federate with others via ActivityPub.
+
+## Status
+
+Early development. See the [architecture plan](docs/architecture.md) and
+[project philosophy](docs/philosophy.md).
+
+## Project Structure
+
+This is a TypeScript monorepo using pnpm workspaces and Turborepo.
+
+```
+apps/
+  planner/        Collaborative route editor (React Router 7 + Yjs + Leaflet)
+  journal/        Activity social platform  (React Router 7 + Fedify + PostGIS)
+
+packages/
+  types/          Shared TypeScript interfaces
+  ui/             Shared React components (Tailwind)
+  map/            Leaflet map wrappers
+  gpx/            GPX parsing and generation
+  i18n/           Internationalization (English + German)
+```
+
+## Getting Started
+
+Prerequisites: Node.js 20+, pnpm
+
+```bash
+# Clone
+git clone https://github.com/trails-cool/trails.git
+cd trails
+
+# Install dependencies
+pnpm install
+
+# Start development
+turbo dev
+```
+
+## Development Tools
+
+This project uses AI-assisted, spec-driven development. See
+[docs/tooling.md](docs/tooling.md) for details.
+
+| Tool | Purpose |
+|------|---------|
+| [cmux](https://cmux.dev) | Native macOS terminal for running multiple AI coding sessions |
+| [Claude Code](https://claude.ai/claude-code) | AI coding assistant (primary development tool) |
+| [Crit](https://github.com/tomasz-tomczyk/crit) | Browser-based inline code review |
+| [OpenSpec](https://openspec.dev) | Spec-driven development workflow |
+
+## Self-Hosting
+
+The Journal is designed to be self-hosted. A single Docker Compose file gets
+you running:
+
+```bash
+curl -O https://raw.githubusercontent.com/trails-cool/trails/main/infrastructure/docker-compose.yml
+docker compose up -d
+```
+
+See [docs/architecture.md](docs/architecture.md) for details on self-hosting
+configuration.
+
+## Philosophy
+
+- **Privacy by design** — The Planner collects zero user data
+- **Data ownership** — Export everything, self-host, no lock-in
+- **Open source** — MIT licensed, built on open standards
+- **Simplicity** — Start simple, add complexity only when needed
+
+Read more: [docs/philosophy.md](docs/philosophy.md)
+
+## Contributing
+
+Human contributions are welcome! This project is built with AI-assisted
+development (Claude Code + OpenSpec), but we value human judgment, design taste,
+and community input.
+
+## License
+
+MIT