Critical fixes and project rename to Rendiff

[alokemajumder]

Summary

This PR includes critical security fixes, project renaming, and FastAPI 0.124.0 upgrade with modern patterns.

Security & Stability Fixes

• Fixed Docker compose conflict: Removed container_name from services using replicas > 1
• Enhanced SSRF protection: Added proper CIDR range checking for private networks (IPv4/IPv6)
• Fixed async webhook calls: Added asyncio.run() wrapper for webhook calls in sync error handlers
• Removed default credentials: Changed default passwords to dev_only_password_change_me with warnings
• Consolidated operation limits: Added MAX_OPERATIONS_PER_JOB config setting (default: 50)
• Fixed async I/O: Added cached get_storage_config() to avoid blocking I/O in async context

Project Rename (ffmpeg-api → rendiff)

• Updated all documentation references
• Updated Kubernetes deployment configs
• Updated monitoring dashboards and alerts
• Renamed dashboard file to rendiff-production.json
• Updated backup and disaster recovery scripts
• Updated database defaults (rendiff_user, rendiff database)

FastAPI 0.124.0 Upgrade

• Updated dependencies: FastAPI 0.124.0, Pydantic 2.10.3, Starlette 0.45.2
• Annotated type hints: Using Doc for better documentation
• Typed dependencies: DatabaseSession, RequiredAPIKey aliases
• Enhanced Pydantic models: computed_field, json_schema_extra with examples
• Improved OpenAPI: Tag descriptions, Swagger UI customization, error response schemas
• Separate schemas: Enabled separate_input_output_schemas for cleaner API docs

Files Changed

• 48+ files modified across all components

Test Plan

• Docker compose config validates successfully
• No remaining ffmpeg-api references
• Git remote updated to new repository URL
• Manual testing of API endpoints
• Verify Swagger UI loads with new documentation
• Test API key authentication flow