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>

package.json

@@ -0,0 +1,17 @@
+{
+  "name": "trails.cool",
+  "private": true,
+  "description": "Collaborative route planning + federated activity sharing for outdoor enthusiasts",
+  "license": "MIT",
+  "packageManager": "pnpm@10.6.5",
+  "engines": {
+    "node": ">=20"
+  },
+  "scripts": {
+    "dev": "turbo dev",
+    "build": "turbo build",
+    "lint": "turbo lint",
+    "test": "turbo test",
+    "typecheck": "turbo typecheck"
+  }
+}