feat: Complete migration from Prefect to Temporal

BREAKING CHANGE: Replaces Prefect workflow orchestration with Temporal

## Major Changes
- Replace Prefect with Temporal for workflow orchestration
- Implement vertical worker architecture (rust, android)
- Replace Docker registry with MinIO for unified storage
- Refactor activities to be co-located with workflows
- Update all API endpoints for Temporal compatibility

## Infrastructure
- New: docker-compose.temporal.yaml (Temporal + MinIO + workers)
- New: workers/ directory with rust and android vertical workers
- New: backend/src/temporal/ (manager, discovery)
- New: backend/src/storage/ (S3-cached storage with MinIO)
- New: backend/toolbox/common/ (shared storage activities)
- Deleted: docker-compose.yaml (old Prefect setup)
- Deleted: backend/src/core/prefect_manager.py
- Deleted: backend/src/services/prefect_stats_monitor.py
- Deleted: Docker registry and insecure-registries requirement

## Workflows
- Migrated: security_assessment workflow to Temporal
- New: rust_test workflow (example/test workflow)
- Deleted: secret_detection_scan (Prefect-based, to be reimplemented)
- Activities now co-located with workflows for independent testing

## API Changes
- Updated: backend/src/api/workflows.py (Temporal submission)
- Updated: backend/src/api/runs.py (Temporal status/results)
- Updated: backend/src/main.py (727 lines, TemporalManager integration)
- Updated: All 16 MCP tools to use TemporalManager

## Testing
- ✅ All services healthy (Temporal, PostgreSQL, MinIO, workers, backend)
- ✅ All API endpoints functional
- ✅ End-to-end workflow test passed (72 findings from vulnerable_app)
- ✅ MinIO storage integration working (target upload/download, results)
- ✅ Worker activity discovery working (6 activities registered)
- ✅ Tarball extraction working
- ✅ SARIF report generation working

## Documentation
- ARCHITECTURE.md: Complete Temporal architecture documentation
- QUICKSTART_TEMPORAL.md: Getting started guide
- MIGRATION_DECISION.md: Why we chose Temporal over Prefect
- IMPLEMENTATION_STATUS.md: Migration progress tracking
- workers/README.md: Worker development guide

## Dependencies
- Added: temporalio>=1.6.0
- Added: boto3>=1.34.0 (MinIO S3 client)
- Removed: prefect>=3.4.18

backend/Dockerfile

@@ -17,25 +17,21 @@ RUN apt-get update && apt-get install -y \
 
 # Docker client configuration removed - localhost:5001 doesn't require insecure registry config
 
-# Install uv for faster package management
-RUN pip install uv
-
 # Copy project files
 COPY pyproject.toml ./
-COPY uv.lock ./
 
-# Install dependencies
-RUN uv sync --no-dev
+# Install dependencies with pip
+RUN pip install --no-cache-dir -e .
 
 # Copy source code
 COPY . .
 
-# Expose port
-EXPOSE 8000
+# Expose ports (API on 8000, MCP on 8010)
+EXPOSE 8000 8010
 
 # Health check
 HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
     CMD curl -f http://localhost:8000/health || exit 1
 
 # Start the application
-CMD ["uv", "run", "uvicorn", "src.main:app", "--host", "0.0.0.0", "--port", "8000"]
+CMD ["uvicorn", "src.main:app", "--host", "0.0.0.0", "--port", "8000"]