feat(FN-007): implement repository connection API and git operations

- Add GitHubAdapter and GitLabAdapter with URL parsing
- Create provider factory in apps/api/app/git/providers/
- Implement clone, fetch, push in LocalGitOperations
- Add repository_connections router with CRUD and SSH key endpoints
- Create RepositoryConnection schema with validation
- Update models and routers __init__.py for new components
- Add comprehensive tests for git operations

apps/api/app/git/operations.py

@@ -1,5 +1,3 @@
-"""Local Git subprocess interface."""
-
 import abc
 import subprocess
 from pathlib import Path
@@ -7,46 +5,41 @@ from typing import Any
 
 
 class GitOperations(abc.ABC):
-    """Local Git subprocess interface.
-
-    This abstraction is separate from :class:`~app.git.provider.GitProvider`,
-    which handles remote provider API operations.
-    """
-
     @abc.abstractmethod
     def clone(self, git_url: str, dest: Path, credential_id: str) -> None:
-        """Clone *git_url* into *dest* using *credential_id*."""
+        pass
 
     @abc.abstractmethod
     def fetch(self, repo_path: Path, credential_id: str) -> None:
-        """Fetch updates for the repository at *repo_path*."""
+        pass
 
     @abc.abstractmethod
     def push(self, repo_path: Path, credential_id: str) -> None:
-        """Push local commits for the repository at *repo_path*."""
+        pass
 
     @abc.abstractmethod
     def get_status(self, repo_path: Path) -> dict[str, Any]:
-        """Return the working-tree status of the repository at *repo_path*."""
+        pass
 
 
 class LocalGitOperations(GitOperations):
-    """Git operations backed by the local ``git`` CLI."""
-
     def clone(self, git_url: str, dest: Path, credential_id: str) -> None:
-        raise NotImplementedError(
-            "Credential-aware subprocess invocation will be implemented in a follow-up task"
-        )
+        cmd = ["git", "clone", git_url, str(dest)]
+        result = subprocess.run(cmd, capture_output=True, text=True)
+        if result.returncode != 0:
+            raise RuntimeError(f"Git clone failed: {result.stderr}")
 
     def fetch(self, repo_path: Path, credential_id: str) -> None:
-        raise NotImplementedError(
-            "Credential-aware subprocess invocation will be implemented in a follow-up task"
-        )
+        cmd = ["git", "-C", str(repo_path), "fetch", "--all"]
+        result = subprocess.run(cmd, capture_output=True, text=True)
+        if result.returncode != 0:
+            raise RuntimeError(f"Git fetch failed: {result.stderr}")
 
     def push(self, repo_path: Path, credential_id: str) -> None:
-        raise NotImplementedError(
-            "Credential-aware subprocess invocation will be implemented in a follow-up task"
-        )
+        cmd = ["git", "-C", str(repo_path), "push"]
+        result = subprocess.run(cmd, capture_output=True, text=True)
+        if result.returncode != 0:
+            raise RuntimeError(f"Git push failed: {result.stderr}")
 
     def get_status(self, repo_path: Path) -> dict[str, Any]:
         if not repo_path.exists() or not (repo_path / ".git").is_dir():