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>

tests/conftest.py

@@ -0,0 +1,59 @@
+"""Pytest configuration and shared fixtures for test suite."""
+
+import pytest
+
+
+@pytest.fixture
+def sample_gitea_config():
+    """Provide sample Gitea configuration for tests."""
+    return {
+        "gitea_url": "https://gitea.test.com",
+        "gitea_token": "test_token_123",
+        "gitea_owner": "test_owner",
+        "gitea_repo": "test_repo",
+    }
+
+
+@pytest.fixture
+def sample_tools_list():
+    """Provide sample MCP tools list for testing."""
+    return [
+        {
+            "name": "list_issues",
+            "description": "List issues in repository",
+            "inputSchema": {
+                "type": "object",
+                "properties": {
+                    "state": {"type": "string", "enum": ["open", "closed", "all"]},
+                },
+            },
+        },
+        {
+            "name": "create_issue",
+            "description": "Create a new issue",
+            "inputSchema": {
+                "type": "object",
+                "properties": {
+                    "title": {"type": "string"},
+                    "body": {"type": "string"},
+                },
+                "required": ["title"],
+            },
+        },
+        {
+            "name": "list_labels",
+            "description": "List labels in repository",
+            "inputSchema": {"type": "object", "properties": {}},
+        },
+    ]
+
+
+@pytest.fixture
+def sample_mcp_response(sample_tools_list):
+    """Provide sample MCP list_tools response."""
+    return {
+        "tools": sample_tools_list,
+        "meta": {
+            "version": "1.0",
+        },
+    }