feat: implement git repository management

- Add backend API for git repository CRUD (create, list, delete)
- Support bare repository initialization and mirror cloning
- Add cascade delete for repositories when project is deleted
- Add frontend page for repository management per project
- Update project page with link to repositories
- Add repo_base_path to config
- Quality gates: ruff, mypy, typecheck, lint, build all pass

apps/web/src/router.tsx

@@ -6,6 +6,7 @@ import { DashboardPage } from "./pages/dashboard";
 import { LoginRedirectPage, NotFoundPage, PlaceholderPage } from "./pages/placeholder";
 import { ProfilePage } from "./pages/profile";
 import { ProjectsPage } from "./pages/projects";
+import { GitRepositoriesPage } from "./pages/git-repositories";
 import { SSHKeysPage } from "./pages/ssh-keys";
 
 export const AppRouter = () => {
@@ -22,7 +23,7 @@ export const AppRouter = () => {
       >
         <Route index element={<DashboardPage />} />
         <Route path="projects" element={<ProjectsPage />} />
-        <Route path="repositories" element={<PlaceholderPage title="Repositories" />} />
+        <Route path="projects/:projectId/repositories" element={<GitRepositoriesPage />} />
         <Route path="ssh-keys" element={<SSHKeysPage />} />
         <Route path="profile" element={<ProfilePage />} />
         <Route path="settings" element={<PlaceholderPage title="Settings" />} />