refactor: rename frontend API files to kebab-case

Renamed:
- git_repositories.ts → git-repositories.ts
- ssh_keys.ts → ssh-keys.ts
- tool_types.ts → tool-types.ts
- tool_types.test.ts → tool-types.test.ts

Updated all imports across components, pages, and hooks.

Quality gates: verified no remaining old imports.

apps/web/src/api/tool-types.test.ts

@@ -6,7 +6,7 @@ import {
   listToolTypes,
   updateToolType,
   validateToolType,
-} from "../api/tool_types";
+} from "../api/tool-types";
 
 const mockGet = vi.fn();
 const mockPost = vi.fn();