refactor: extract focused clients from GiteaClient (Slices 1-6)

- Create gitea/issues_client.py with IssuesClient class (9 methods)
- Create gitea/prs_client.py with PullRequestsClient class (17 methods)
- Create gitea/files_client.py with FilesClient class (4 methods)
- Create gitea/notifications_client.py with NotificationsClient class (2 methods)
- Create gitea/repos_client.py with ReposClient class (2 methods)
- Create gitea/__init__.py to export all client classes
- Remove delegation methods from GiteaClient (now ~70 lines)
- Update all callers to use sub-clients (client.issues, client.prs, etc.)
- Update test files to mock sub-client attributes

GiteaClient is now a facade that provides access to focused sub-clients:
- repos: Repository operations (ReposClient)
- issues: Issue operations (IssuesClient)
- prs: Pull request operations (PullRequestsClient)
- files: File and git ref operations (FilesClient)
- notifications: Notification operations (NotificationsClient)

Refs: #godclass-refactor

tests/test_client.py

@@ -11,7 +11,7 @@ def test_gitea_client_list_repo_issues() -> None:
         mock_get.return_value = mock_response
 
         # Test default parameter ("open")
-        client.list_repo_issues("owner", "repo")
+        client.issues.list_repo_issues("owner", "repo")
         mock_get.assert_called_once()
         args, _ = mock_get.call_args
         assert "type=issues" in args[0]
@@ -20,7 +20,7 @@ def test_gitea_client_list_repo_issues() -> None:
         mock_get.reset_mock()
 
         # Test custom parameter ("closed")
-        client.list_repo_issues("owner", "repo", state="closed")
+        client.issues.list_repo_issues("owner", "repo", state="closed")
         mock_get.assert_called_once()
         args, _ = mock_get.call_args
         assert "type=issues" in args[0]
@@ -36,7 +36,7 @@ def test_gitea_client_list_repo_pull_requests() -> None:
         mock_get.return_value = mock_response
 
         # Test default parameter ("open")
-        client.list_repo_pull_requests("owner", "repo")
+        client.prs.list_repo_pull_requests("owner", "repo")
         mock_get.assert_called_once()
         args, _ = mock_get.call_args
         assert "state=open" in args[0]
@@ -44,7 +44,7 @@ def test_gitea_client_list_repo_pull_requests() -> None:
         mock_get.reset_mock()
 
         # Test custom parameter ("closed")
-        client.list_repo_pull_requests("owner", "repo", state="closed")
+        client.prs.list_repo_pull_requests("owner", "repo", state="closed")
         mock_get.assert_called_once()
         args, _ = mock_get.call_args
         assert "state=closed" in args[0]
@@ -55,14 +55,17 @@ def test_gitea_client_list_assigned_issues() -> None:
     user_mock: MagicMock = MagicMock()
     user_mock.login = "testuser"
 
-    with patch.object(client, "get_authenticated_user", return_value=user_mock), \
-            patch("httpx.Client.get") as mock_get:
+    with (
+        patch.object(client.repos, "get_authenticated_user", return_value=user_mock),
+        patch.object(client.issues, "_get_user", return_value=user_mock),
+        patch("httpx.Client.get") as mock_get,
+    ):
         mock_response: MagicMock = MagicMock()
         mock_response.status_code = 200
         mock_response.json.return_value = []
         mock_get.return_value = mock_response
 
-        client.list_assigned_issues("owner", "repo")
+        client.issues.list_assigned_issues("owner", "repo")
         mock_get.assert_called_once()
         args, _ = mock_get.call_args
         assert "type=issues" in args[0]
@@ -74,18 +77,36 @@ def test_gitea_client_list_assigned_pull_requests() -> None:
     user_mock: MagicMock = MagicMock()
     user_mock.login = "testuser"
 
-    with patch.object(client, "get_authenticated_user", return_value=user_mock), \
-            patch("httpx.Client.get") as mock_get:
+    with (
+        patch.object(client.repos, "get_authenticated_user", return_value=user_mock),
+        patch.object(client.prs, "_get_user", return_value=user_mock),
+        patch("httpx.Client.get") as mock_get,
+    ):
         mock_response: MagicMock = MagicMock()
         mock_response.status_code = 200
         mock_response.json.return_value = [
-            {"number": 1, "title": "PR 1", "assignee": {"login": "testuser"}, "user": {"login": "otheruser"}},
-            {"number": 2, "title": "PR 2", "assignee": None, "user": {"login": "testuser"}},
-            {"number": 3, "title": "PR 3", "assignee": {"login": "otheruser"}, "user": {"login": "otheruser"}}
+            {
+                "number": 1,
+                "title": "PR 1",
+                "assignee": {"login": "testuser"},
+                "user": {"login": "otheruser"},
+            },
+            {
+                "number": 2,
+                "title": "PR 2",
+                "assignee": None,
+                "user": {"login": "testuser"},
+            },
+            {
+                "number": 3,
+                "title": "PR 3",
+                "assignee": {"login": "otheruser"},
+                "user": {"login": "otheruser"},
+            },
         ]
         mock_get.return_value = mock_response
 
-        res = client.list_assigned_pull_requests("owner", "repo")
+        res = client.prs.list_assigned_pull_requests("owner", "repo")
         mock_get.assert_called_once()
         assert len(res) == 2
         numbers = [pr.number for pr in res]
@@ -106,7 +127,7 @@ def test_gitea_client_list_unread_notifications() -> None:
         mock_get.return_value = mock_response
 
         # Test without since
-        res = client.list_unread_notifications()
+        res = client.notifications.list_unread_notifications()
         mock_get.assert_called_once()
         _, kwargs = mock_get.call_args
         assert kwargs.get("params") == {"all": "false"}
@@ -116,20 +137,23 @@ def test_gitea_client_list_unread_notifications() -> None:
         mock_get.reset_mock()
 
         # Test with since
-        res = client.list_unread_notifications(since="2026-06-30T21:41:16+02:00")
+        res = client.notifications.list_unread_notifications(
+            since="2026-06-30T21:41:16+02:00"
+        )
         mock_get.assert_called_once()
         _, kwargs = mock_get.call_args
-        assert kwargs.get("params") == {"all": "false", "since": "2026-06-30T21:41:16+02:00"}
+        assert kwargs.get("params") == {
+            "all": "false",
+            "since": "2026-06-30T21:41:16+02:00",
+        }
 
 
 import pytest
 
+
 def test_gitea_client_get_authenticated_user_failure() -> None:
     client: GiteaClient = GiteaClient()
     with patch("httpx.Client.get") as mock_get:
         mock_get.side_effect = Exception("Connection error")
         with pytest.raises(RuntimeError, match="Could not get authenticated user"):
-            client.get_authenticated_user()
-
-
-
+            client.repos.get_authenticated_user()