chore: initial project setup with documentation and design assets

Add project foundation: CLAUDE.md, requirements tracking system,
technical architecture docs, Firestore setup guide, device testing guide,
and Stitch design mockups for Precision Vitality app.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,41 @@
+# Dependencies
+node_modules/
+.npm
+
+# Build
+www/
+dist/
+
+# Capacitor native projects
+android/
+ios/
+
+# Environment files (contain secrets)
+src/environments/environment.ts
+src/environments/environment.prod.ts
+
+# Firebase
+.firebase/
+google-services.json
+GoogleService-Info.plist
+functions/node_modules/
+functions/lib/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Keystore (signing keys)
+*.keystore
+*.jks
+
+# Misc
+*.log
+npm-debug.log*