Typecheck failures in packages/opencode

[jroth1111]

Summary

bun run --cwd packages/opencode typecheck fails with TS errors.

Errors (sample)

• src/session/prompt.ts: part.state.time not narrowed on pending state.
• src/session/todo.ts: Task.Info typing mismatches (status string vs union, tracker.mode string vs union).
• src/task/index.ts: arity/type mismatches (tracker.mode type).
• src/task/repo.ts: tracker.mode mismatch and missing agent on run type.
• src/tool/todo.ts: tool return typing mismatch for metadata.todo.

Reproducible on dev branch.