test: add 106 unit + smoke tests, 93% coverage

- pytest + respx + pytest-cov added as dev dependencies
- tests/smoke/test_registration.py: verify all 66 tools registered and unique
- tests/unit/: 12 files covering every tool — HTTP method, URL, params/body, errors
- tests/config.test.json + conftest.py: zero-network test setup via GITEA_CONFIG
- CLAUDE.md: developer guide with testing philosophy, pyramid, and commands
- server/gitea_mcp.py: get_commit, list_pr_files tools added
- README.md: tool count corrected to 66

tests/unit/test_users_orgs.py

@@ -0,0 +1,90 @@
+import pytest
+import httpx
+import respx
+from server.gitea_mcp import (
+    get_user, search_users, list_my_orgs, get_org,
+    list_org_repos, list_org_members, list_org_teams,
+)
+
+BASE = "https://gitea.test/api/v1"
+
+
+@respx.mock
+def test_get_user():
+    route = respx.get(f"{BASE}/users/alice").mock(
+        return_value=httpx.Response(200, json={"login": "alice", "id": 42})
+    )
+    result = get_user("alice")
+    assert route.called
+    assert result["login"] == "alice"
+
+
+@respx.mock
+def test_get_user_not_found():
+    respx.get(f"{BASE}/users/nobody").mock(
+        return_value=httpx.Response(404, json={"message": "not found"})
+    )
+    with pytest.raises(RuntimeError, match="404"):
+        get_user("nobody")
+
+
+@respx.mock
+def test_search_users():
+    route = respx.get(f"{BASE}/users/search").mock(
+        return_value=httpx.Response(200, json={"data": [{"login": "alice"}]})
+    )
+    result = search_users("ali")
+    assert route.called
+    params = dict(route.calls[0].request.url.params)
+    assert params["q"] == "ali"
+    assert params["limit"] == "10"
+
+
+@respx.mock
+def test_list_my_orgs():
+    route = respx.get(f"{BASE}/user/orgs").mock(
+        return_value=httpx.Response(200, json=[{"name": "myorg"}])
+    )
+    result = list_my_orgs()
+    assert route.called
+    assert result[0]["name"] == "myorg"
+
+
+@respx.mock
+def test_get_org():
+    route = respx.get(f"{BASE}/orgs/myorg").mock(
+        return_value=httpx.Response(200, json={"name": "myorg", "full_name": "My Org"})
+    )
+    result = get_org("myorg")
+    assert route.called
+    assert result["name"] == "myorg"
+
+
+@respx.mock
+def test_list_org_repos():
+    route = respx.get(f"{BASE}/orgs/myorg/repos").mock(
+        return_value=httpx.Response(200, json=[{"name": "repo1"}])
+    )
+    result = list_org_repos("myorg")
+    assert route.called
+    assert dict(route.calls[0].request.url.params)["limit"] == "50"
+
+
+@respx.mock
+def test_list_org_members():
+    route = respx.get(f"{BASE}/orgs/myorg/members").mock(
+        return_value=httpx.Response(200, json=[{"login": "bob"}])
+    )
+    result = list_org_members("myorg")
+    assert route.called
+    assert result[0]["login"] == "bob"
+
+
+@respx.mock
+def test_list_org_teams():
+    route = respx.get(f"{BASE}/orgs/myorg/teams").mock(
+        return_value=httpx.Response(200, json=[{"id": 1, "name": "developers"}])
+    )
+    result = list_org_teams("myorg")
+    assert route.called
+    assert result[0]["name"] == "developers"