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>

CLAUDE.md

@@ -0,0 +1,90 @@
+# CLAUDE.md
+
+## Project Overview
+
+trails.cool is a federated, self-hostable platform for outdoor enthusiasts with two apps:
+
+- **Planner** (`apps/planner`) — Stateless collaborative route editor. Real-time editing via Yjs, routing via BRouter, no user accounts, sessions are anonymous and ephemeral.
+- **Journal** (`apps/journal`) — Federated social platform for routes and activities. User accounts, ActivityPub federation via Fedify, PostgreSQL + PostGIS.
+
+Full architecture: `docs/architecture.md`
+Philosophy: `docs/philosophy.md`
+OpenSpec change: `openspec/changes/phase-1-mvp/`
+
+## Principles
+
+- **Privacy-first**: The Planner collects zero user data. The Journal documents all data collection in a privacy manifest. Never add tracking, analytics, or data collection without updating the manifest.
+- **Data ownership**: All user data must be exportable in open formats (GPX, JSON). Never create data lock-in.
+- **Simplicity**: Start with the simplest thing that works. Don't add abstractions, config options, or features unless real users need them.
+- **Open standards**: Use GPX, ActivityPub, OpenStreetMap, WebFinger. Don't invent proprietary formats.
+- **Inclusive language**: Use "host" not "master", "allowlist" not "whitelist", etc.
+
+## Tech Stack
+
+- **Language**: TypeScript (strict mode)
+- **Frontend**: React + Tailwind CSS + React Router 7 (Remix stack)
+- **Maps**: Leaflet + OpenStreetMap tiles
+- **CRDT**: Yjs + y-websocket (Planner only)
+- **Federation**: Fedify (Journal only, Phase 2)
+- **Database**: PostgreSQL + PostGIS
+- **Media storage**: S3-compatible (Garage)
+- **Routing engine**: BRouter (Java, runs as separate Docker container)
+- **i18n**: react-i18next (English + German)
+- **Monorepo**: pnpm workspaces + Turborepo
+
+## Repository Structure
+
+```
+apps/
+  planner/          — Planner app (React Router 7)
+  journal/          — Journal app (React Router 7 + Fedify)
+packages/
+  types/            — Shared TypeScript interfaces (Route, Activity, Waypoint)
+  ui/               — Shared React components (Tailwind)
+  map/              — Leaflet map wrappers and tile layer configs
+  gpx/              — GPX parsing, generation, validation
+  i18n/             — react-i18next config + translations
+infrastructure/     — Terraform + Docker Compose
+openspec/           — OpenSpec specs and changes
+docs/               — Architecture, philosophy, tooling docs
+docker/brouter/     — BRouter Docker image
+```
+
+## Development Commands
+
+```bash
+pnpm install          # Install dependencies
+turbo dev             # Start both apps in dev mode
+turbo build           # Build all packages and apps
+turbo typecheck       # Type-check all packages
+turbo lint            # Lint all packages
+turbo test            # Run tests
+```
+
+## Code Conventions
+
+- All user-facing strings must use i18n (`useTranslation()` hook, never hardcode strings)
+- Use `@trails-cool/types` for shared interfaces — don't duplicate type definitions
+- Map components go in `@trails-cool/map`, not in individual apps
+- GPX parsing/generation goes in `@trails-cool/gpx`
+- Database schemas: `planner.*` for Planner data, `journal.*` for Journal data
+- Route geometry must be stored as PostGIS LineString (extracted from GPX on save)
+
+## Key Architecture Decisions
+
+- **Planner is stateless**: No user accounts, no persistent user data. Sessions are anonymous.
+- **Journal is the source of truth**: Routes live on the owner's Journal instance.
+- **Routing host pattern**: One client per Planner session talks to BRouter (elected via Yjs awareness).
+- **JWT callbacks**: Planner saves back to Journal via scoped JWT tokens in callback URLs.
+- **Sequential versioning**: Route versions are v1, v2, v3. Yjs state vectors enable conflict-free merging.
+- **Single domain**: Each instance uses one domain for both web UI and ActivityPub handles.
+- **Simple permissions**: View + Edit only. No fine-grained permissions.
+
+## OpenSpec Workflow
+
+Specs live in `openspec/`. Use these slash commands:
+
+- `/opsx:propose` — Create a new change with proposal, design, specs, and tasks
+- `/opsx:apply` — Implement tasks from an existing change
+- `/opsx:explore` — Think through ideas before proposing
+- `/opsx:archive` — Archive a completed change