Initial commit: dating app backend (Go/Gin/GORM/Postgres)

Phone+OTP auth, staged onboarding, admin approval workflow, and a
full discovery/swipe/match/chat system with photo upload and
approximate distance (haversine) based on user location.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.env.example

@@ -0,0 +1,20 @@
+APP_ENV=development
+APP_PORT=8080
+
+DB_HOST=localhost
+DB_PORT=5432
+DB_USER=postgres
+DB_PASSWORD=postgres
+DB_NAME=dating_app
+DB_SSLMODE=disable
+
+JWT_ACCESS_SECRET=test-access-secret
+JWT_REFRESH_SECRET=test-refresh-secret
+JWT_ACCESS_TTL_MINUTES=1440
+JWT_REFRESH_TTL_DAYS=30
+
+OTP_EXPIRY_SECONDS=180
+OTP_LENGTH=4
+OTP_HASH_SECRET=test-otp-secret
+
+ADMIN_BOOTSTRAP_PHONE=09120000000