Initial monorepo setup with architecture plan

- Monorepo structure: apps/ (planner, journal) + packages/ (ui, types, map, gpx, i18n)
- Tooling: pnpm workspaces + Turborepo
- Architecture plan documenting all resolved decisions from design review
- Shared types package with Route, Activity, and Waypoint interfaces
- MIT license

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

packages/map/src/index.ts

@@ -0,0 +1,5 @@
+/**
+ * Map rendering utilities for trails.cool
+ * Leaflet wrappers, tile layer configs, overlay management
+ */
+export {};