[feat] Add comprehensive unit tests for TaskQueue operations

- Add MockTaskQueue class with dependency injection for isolated testing
- Test core operations: queueing, processing, batch tracking, state management
- Test thread safety: concurrent access, worker lifecycle, exception handling
- Test integration workflows: full task processing with WebSocket updates
- Test edge cases: empty queues, invalid data, cleanup scenarios
- Solve heapq compatibility by wrapping items in priority tuples
- Include pytest configuration and test runner script
- All 15 tests passing with proper async/threading support

Testing covers:
✅ Task queueing with Pydantic validation
✅ Batch history tracking and persistence
✅ Thread-safe concurrent operations
✅ Worker thread lifecycle management
✅ WebSocket message delivery tracking
✅ State snapshots and error conditions

run_tests.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+"""
+Simple test runner for ComfyUI-Manager tests.
+
+Usage:
+    python run_tests.py                    # Run all tests
+    python run_tests.py -k test_task_queue # Run specific tests
+    python run_tests.py --cov             # Run with coverage
+"""
+
+import sys
+import subprocess
+from pathlib import Path
+
+def main():
+    """Run pytest with appropriate arguments"""
+    # Ensure we're in the project directory
+    project_root = Path(__file__).parent
+    
+    # Base pytest command
+    cmd = [sys.executable, "-m", "pytest"]
+    
+    # Add any command line arguments passed to this script
+    cmd.extend(sys.argv[1:])
+    
+    # Add default arguments if none provided
+    if len(sys.argv) == 1:
+        cmd.extend([
+            "tests/",
+            "-v",
+            "--tb=short"
+        ])
+    
+    print(f"Running: {' '.join(cmd)}")
+    print(f"Working directory: {project_root}")
+    
+    # Run pytest
+    result = subprocess.run(cmd, cwd=project_root)
+    sys.exit(result.returncode)
+
+if __name__ == "__main__":
+    main()