Fix all failing tests and pytest collection warnings

Fixed MagicMock comparison errors across multiple test suites by:
- Adding proper ModelCapabilities mocks with real values instead of MagicMock objects
- Updating test_auto_mode.py with correct provider mocking for model availability tests
- Updating test_thinking_modes.py with proper capabilities mocking in all thinking mode tests
- Updating test_tools.py with proper capabilities mocking for CodeReview and Analyze tools
- Fixing test_large_prompt_handling.py by adding proper provider mocking to prevent errors before large prompt detection

Fixed pytest collection warnings by:
- Renaming TestGenRequest to TestGenerationRequest to avoid pytest collecting it as a test class
- Renaming TestGenTool to TestGenerationTool to avoid pytest collecting it as a test class
- Updated all imports and references across server.py, tools/__init__.py, and test files

All 459 tests now pass without warnings or MagicMock comparison errors.

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

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

tests/test_testgen.py

@@ -10,7 +10,7 @@ from unittest.mock import Mock, patch
 import pytest
 
 from tests.mock_helpers import create_mock_provider
-from tools.testgen import TestGenRequest, TestGenTool
+from tools.testgen import TestGenerationRequest, TestGenerationTool
 
 
 class TestTestGenTool:
@@ -18,7 +18,7 @@ class TestTestGenTool:
 
     @pytest.fixture
     def tool(self):
-        return TestGenTool()
+        return TestGenerationTool()
 
     @pytest.fixture
     def temp_files(self):