[romiluz13]: **Acceptance criteria (added 13 Oct 2026):** - [ ] `python scripts/demo.py --uri [mongod without mongot]` exits with one clear message naming the missing Search/Vector Search capability and the options (atlas-local via docker compose, or Atlas), with no traceback. - [ ] The same message appears when the failing command is `createSearchIndexes` (code 59). - [ ] The existing connection-error message is unchanged.

Context: GitHub issue romiluz13/Hybrid-Search-RAG#28 (open, 1 comments, reported 2026-10-11): Found in a user-0 run. README says "Fail-Fast Support: explicit capability errors", but a plain MongoDB gives a long traceback. **Steps** 1. Run Community `mongod` 7.0.14 (replica set, no `mongot`), Python 3.11, `uv pip install -e ".[all]"`. 2. `python scripts/demo.py --uri "mongodb://YOUR_HOST:27017/?directConnection=true"` **Actual** About 30 lines of pymongo traceback ending in: ``` pymongo.errors.OperationFailure: no such command: 'createSearchIndexes', full error: {'ok': 0.0, 'errmsg': "no such command: 'createSearchIndexes'", 'code': 59, 'codeName': 'CommandNotFound', ...} ``` The conn