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/api/src/main.py

@@ -2,6 +2,7 @@ from fastapi import FastAPI
 from fastapi.staticfiles import StaticFiles
 
 from src.api.auth import router as auth_router
+from src.api.git_repositories import router as git_repositories_router
 from src.api.projects import router as projects_router
 from src.api.ssh_keys import router as ssh_keys_router
 from src.api.users import router as users_router
@@ -11,4 +12,5 @@ app.include_router(auth_router)
 app.include_router(projects_router)
 app.include_router(users_router)
 app.include_router(ssh_keys_router)
+app.include_router(git_repositories_router)
 app.mount("/uploads", StaticFiles(directory="uploads"), name="uploads")