Fix TypeScript errors and clean up unused imports

- Remove unused fs import from app.ts
- Remove unused LLM import and missing module reference from server.ts
- Fix parameter naming inconsistency in fetch.ts execute function
- Add missing metadata property to fetch.ts return statement
- Update test file to use correct API signatures and parameter names
- Remove unused parameters from example.ts

🤖 Generated with opencode
Co-Authored-By: opencode <noreply@opencode.ai>

packages/opencode/src/app/app.ts

@@ -1,4 +1,3 @@
-import fs from "fs/promises"
 import { Log } from "../util/log"
 import { Context } from "../util/context"
 import { Filesystem } from "../util/filesystem"