feat: Configure database with Prisma and MySQL spatial support (Task 22)

- Set up MySQL 8.0+ with spatial data support (POINT SRID 4326)
- Created Prisma schema with all models (User, Report, Event, etc.)
- Added Clerk authentication support (clerk_id field)
- Configured spatial indexes on location fields for performance
- Created database migrations and applied to MySQL
- Built spatial query utilities for geographical operations
- Added database connection singleton and health checks
- Created comprehensive documentation and test scripts

Requirements: 1.1, 2.1, 3.2, 4.1

server/prisma/migrations/migration_lock.toml

@@ -0,0 +1,3 @@
+# Please do not edit this file manually
+# It should be added in your version-control system (i.e. Git)
+provider = "mysql"