fix: improve prompts, error messages, and workspace concurrency

- Externalize coordinator, notification, and planning prompts to separate files
- Add workspace mutex for concurrent file operations
- Improve error messages across file_tools, issue_tools, and pr_tools
- Add logging to tool modules for better debugging
- Update tests to match new error message strings

gitea/workspace.py

@@ -3,6 +3,7 @@ import logging
 import subprocess
 import base64
 import shutil
+import threading
 from pathlib import Path
 from urllib.parse import urlparse
 from .config import GITEA_REPOS_ROOT, GITEA_URL, GITEA_TOKEN
@@ -12,12 +13,27 @@ logger: logging.Logger = logging.getLogger("gitea-workspace")
 
 
 class WorkspaceManager:
-    """Manages local workspace for Gitea repositories."""
+    """Manages local workspace for Gitea repositories.
+
+    Uses per-repo threading locks to prevent concurrent git operations
+    on the same repository from causing race conditions.
+    """
+
+    _repo_locks: dict[str, threading.Lock] = {}
+    _locks_lock: threading.Lock = threading.Lock()
 
     def __init__(self) -> None:
         self.root_dir: Path = Path(GITEA_REPOS_ROOT).expanduser().resolve()
         self.root_dir.mkdir(parents=True, exist_ok=True)
 
+    @classmethod
+    def get_repo_lock(cls, repo_full_name: str) -> threading.Lock:
+        """Get or create a thread-safe lock for a specific repository."""
+        with cls._locks_lock:
+            if repo_full_name not in cls._repo_locks:
+                cls._repo_locks[repo_full_name] = threading.Lock()
+            return cls._repo_locks[repo_full_name]
+
     def _configure_repo_user(self, repo_path: Path) -> None:
         try:
             client = GiteaClient()
@@ -70,6 +86,12 @@ class WorkspaceManager:
         return f"{parsed.scheme}://{parsed.netloc}{path}/{repo_full_name}.git"
 
     def sanitize_repo(self, repo_full_name: str, repo_path: Path) -> None:
+        lock = self.get_repo_lock(repo_full_name)
+        with lock:
+            logger.debug(f"Acquired workspace lock for {repo_full_name} (sanitize)")
+            self._sanitize_repo_inner(repo_full_name, repo_path)
+
+    def _sanitize_repo_inner(self, repo_full_name: str, repo_path: Path) -> None:
         try:
             auth_url = self._get_authenticated_url(repo_full_name)
             subprocess.run(
@@ -146,6 +168,14 @@ class WorkspaceManager:
             ) from e
 
     def clone_repo(self, repo_full_name: str, clone_url: str | None = None) -> Path:
+        lock = self.get_repo_lock(repo_full_name)
+        with lock:
+            logger.debug(f"Acquired workspace lock for {repo_full_name} (clone)")
+            return self._clone_repo_inner(repo_full_name, clone_url)
+
+    def _clone_repo_inner(
+        self, repo_full_name: str, clone_url: str | None = None
+    ) -> Path:
         repo_path: Path = self.get_repo_path(repo_full_name)
         if repo_path.exists():
             if not (repo_path / ".git").exists():