Move tests to repository root and update pytest configuration

- Move tests from src/gitea_mcp_remote/tests/ to tests/ (top-level)
- Update pytest.ini to point to new test location
- All imports already use absolute paths (gitea_mcp_remote.*)
- Tests run successfully from new location (28/30 pass, 2 pre-existing failures)

This improves project structure by following standard Python conventions
where tests live at the repository root level rather than inside the
source package.

Closes #21

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

pytest.ini

@@ -1,5 +1,5 @@
 [pytest]
-testpaths = src/gitea_mcp_remote/tests
+testpaths = tests
 python_files = test_*.py
 python_classes = Test*
 python_functions = test_*