Implement unified Oracle mode support with auto-detection

- Unified Dockerfile with thick/thin mode auto-detection
- Single docker-compose.yaml with build arguments
- Auto-detect logic: thick mode for Oracle 10g/11g, thin mode for 12.1+
- Simplified .env configuration with clear mode selection
- Updated admin.py with FORCE_THIN_MODE and INSTANTCLIENTPATH support
- Added comprehensive documentation for both deployment modes
- Container tested successfully with thick mode for Oracle 11g compatibility

🤖 Generated with [Claude Code](https://claude.ai/code)

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

.gitignore

@@ -7,4 +7,10 @@ api/.env
 # Helper/temporary files in docs
 docs/PACK_COMENZI.pck
 docs/completeaza-parteneri-roa.prg  
-docs/info-database.sql
+docs/info-database.sql
+
+# Log files
+admin.log
+
+# Python cache
+__pycache__/