Add Docker deployment and Claude Code documentation

- Add docker-compose.yml for nginx container deployment
- Add CLAUDE.md with project architecture guidance

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+KML Track Editor is a single-page web application for viewing, editing, and navigating KML/GPS tracks on an interactive map. The entire application is contained in `index.html`.
+
+## Development
+
+To run locally, serve via HTTP (required for GPS geolocation API):
+```bash
+python -m http.server 8000
+```
+Then open http://localhost:8000
+
+## Architecture
+
+### Single-File Application
+Everything is in `index.html`:
+- **Lines 1-325**: CSS styles
+- **Lines 326-420**: HTML structure (map, controls sidebar, overlays)
+- **Lines 421-end**: JavaScript application code
+
+### Key Libraries (loaded from CDN)
+- **Leaflet.js 1.9.4**: Map rendering and interaction
+- **leaflet-rotate 0.2.8**: Map rotation for navigation mode
+
+### Core State Variables (around line 457-514)
+- `tracks[]`: All loaded track objects with `{id, name, coords, layer, color}`
+- `selectedTracks[]`: Currently selected tracks for multi-selection operations
+- `currentTool`: Active editing tool ('select', 'draw', 'reshape', 'smooth', 'delete')
+- `navMode`: Whether in navigation mode vs edit mode
+- `currentRoute`: Pathfinding result for navigation
+
+### Major Feature Areas
+
+**Track Editing**:
+- Draw new tracks, reshape existing ones with rope physics, smooth brush tool
+- Track snapping at endpoints (auto-splits target track at snap point)
+- Multi-track selection and merge operations
+- Undo system with 20-step history
+
+**Navigation Mode**:
+- Graph-based pathfinding using Dijkstra's algorithm across connected trails
+- Trail intersections detected within 5 meters (`INTERSECTION_THRESHOLD`)
+- Real-time route recalculation when user deviates >50m from path
+- Map rotation to face direction of travel (uses `map.setBearing()`)
+- Auto-center on GPS position (toggleable)
+- Destination persistence in localStorage
+
+**GPS Integration**:
+- Uses `navigator.geolocation.watchPosition` with backup polling every 3 seconds
+- Requires HTTPS or localhost to function
+
+### File Loading
+- Automatically loads `default.kml` on startup if present
+- KML parsing via DOMParser extracting `<Placemark>` coordinates

docker-compose.yml

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+services:
+  web:
+    image: nginx:alpine
+    ports:
+      - "8080:80"
+    volumes:
+      - ./index.html:/usr/share/nginx/html/index.html:ro
+      - ./default.kml:/usr/share/nginx/html/default.kml:ro
+    restart: unless-stopped