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

gitea/tools/issue_tools.py

@@ -17,14 +17,14 @@ class IssueTools:
 
     def get_issue(self, owner: str, repo: str, issue_number: int) -> str:
         try:
-            issue: IssueModel = self._client.get_issue(owner, repo, issue_number)
+            issue: IssueModel = self._client.issues.get_issue(owner, repo, issue_number)
             return issue.model_dump_json(indent=2)
         except Exception as e:
             return f"Error getting issue: {str(e)}"
 
     def close_issue(self, owner: str, repo: str, issue_number: int) -> str:
         try:
-            self._client.close_issue(owner, repo, issue_number)
+            self._client.issues.close_issue(owner, repo, issue_number)
             return f"Issue #{issue_number} closed successfully."
         except Exception as e:
             return f"Error closing issue: {str(e)}"
@@ -44,7 +44,7 @@ class IssueTools:
             offset: Zero-based comment index to start from (default 0).
         """
         try:
-            comments: list[CommentModel] = self._client.get_issue_comments(
+            comments: list[CommentModel] = self._client.issues.get_issue_comments(
                 owner, repo, issue_number
             )
             total: int = len(comments)
@@ -62,12 +62,12 @@ class IssueTools:
 
     def list_assigned_issues(self) -> list[dict[str, Any]]:
         try:
-            repos = self._client.list_all_user_repos()
+            repos = self._client.repos.list_all_user_repos()
             all_issues: list[dict[str, Any]] = []
             for repo in repos:
                 owner = repo.owner
                 repo_name = repo.name
-                issues = self._client.list_assigned_issues(owner, repo_name)
+                issues = self._client.issues.list_assigned_issues(owner, repo_name)
                 if issues:
                     all_issues.extend(
                         [
@@ -84,7 +84,7 @@ class IssueTools:
 
     def list_issues(self, owner: str, repo: str, state: str = "open") -> str:
         try:
-            issues = self._client.list_repo_issues(owner, repo, state)
+            issues = self._client.issues.list_repo_issues(owner, repo, state)
             if not issues:
                 return f"No issues in {owner}/{repo}."
             summary = [f"#{issue.number}: {issue.title}" for issue in issues]
@@ -102,7 +102,7 @@ class IssueTools:
         assignees: list[str] | None = None,
     ) -> str:
         try:
-            issue = self._client.create_issue(
+            issue = self._client.issues.create_issue(
                 owner, repo, title, body, labels, assignees
             )
             return f"Issue #{issue.number} created successfully in {owner}/{repo}."
@@ -113,7 +113,7 @@ class IssueTools:
         self, owner: str, repo: str, issue_number: int, label: str
     ) -> str:
         try:
-            self._client.add_label(owner, repo, issue_number, label)
+            self._client.issues.add_label(owner, repo, issue_number, label)
             return f"Label '{label}' added to issue #{issue_number}."
         except Exception as e:
             return f"Error adding label to issue #{issue_number}: {e}"
@@ -122,7 +122,7 @@ class IssueTools:
         self, owner: str, repo: str, issue_number: int, body: str
     ) -> str:
         try:
-            self._client.add_comment(owner, repo, issue_number, body)
+            self._client.issues.add_comment(owner, repo, issue_number, body)
             return f"Comment added to issue #{issue_number}."
         except Exception as e:
             return f"Error adding comment to issue #{issue_number}: {e}"