Create test suite for wrapper functionality

This commit implements a comprehensive test suite for the HTTP wrapper components.

Test coverage:
- test_config.py: Configuration loader and validation tests
  - Required field validation
  - URL validation and formatting
  - Port range validation
  - Tool list parsing (enabled/disabled)
  - Environment variable generation
  - .env file loading

- test_filtering.py: Tool filtering tests
  - Passthrough mode (no filtering)
  - Whitelist mode (enabled_tools)
  - Blacklist mode (disabled_tools)
  - Tool list filtering
  - MCP response filtering
  - Edge cases (empty lists, missing names)

- test_middleware.py: HTTP authentication tests
  - BearerAuthMiddleware with/without token
  - Valid/invalid token handling
  - Missing/malformed Authorization headers
  - HTTP status codes (401, 403)
  - HealthCheckBypassMiddleware
  - Custom health check paths
  - Middleware ordering

Test infrastructure:
- conftest.py: Shared fixtures for common test data
- pytest.ini: Test configuration and markers
- Updated dev dependencies with test frameworks

Test execution:
- Run all tests: pytest
- Run with coverage: pytest --cov=gitea_http_wrapper
- Run specific test: pytest src/gitea_http_wrapper/tests/test_config.py

This test suite validates all wrapper components except the main server (which would require integration tests with a real Gitea MCP server).

Closes #17

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

pytest.ini

@@ -0,0 +1,18 @@
+[pytest]
+testpaths = src/gitea_http_wrapper/tests
+python_files = test_*.py
+python_classes = Test*
+python_functions = test_*
+asyncio_mode = auto
+
+# Coverage options
+addopts =
+    --verbose
+    --strict-markers
+    --tb=short
+
+# Markers for test categorization
+markers =
+    unit: Unit tests (fast, no external dependencies)
+    integration: Integration tests (may require external services)
+    slow: Slow-running tests