Initial commit: Set up Garmin Health Lab project structure

- Initialize monorepo with root workspace configuration
- Set up Express.js backend with TypeScript
- Set up React 18 frontend with TypeScript
- Create database schema with SQLite
- Implement project architecture and documentation
- Add development and deployment guidelines

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

.gitignore

@@ -0,0 +1,27 @@
+node_modules/
+dist/
+build/
+*.log
+npm-debug.log*
+.DS_Store
+.env
+.env.local
+.env.*.local
+.idea/
+.vscode/
+*.swp
+*.swo
+~*
+
+# Database
+*.db
+*.sqlite
+*.sqlite3
+
+# API Keys and secrets
+.env.production.local
+config/secrets.json
+
+# Build artifacts
+server/dist/
+client/build/