[Incident][108dev] Questions API 500 due to Cosmos env drift (empty endpoint/database)

## Summary
Questions frontend is failing with internal server errors on:
- GET /api/questions/questions
- GET /api/questions/assemblies

## Observed error
API payload returns:
- Invalid URL scheme or hostname: SplitResult(scheme='', netloc='', path='', query='', fragment='')

## Root cause
`COSMOS_ENDPOINT` and `COSMOS_DATABASE` were empty in `tutor-questions-108dev` runtime environment.

## Immediate remediation plan (live)
- Re-apply Cosmos env baseline to 108dev container apps.
- Re-validate Questions endpoints through APIM.
- Log actions and evidence in #139.

Related: #139

Start with related issue #139, then review the Cosmos environment baseline for the tutor-questions-108dev container apps. Re-validate GET /api/questions/questions and GET /api/questions/assemblies through APIM; done means both endpoints no longer return 500 errors and the remediation evidence is logged in #139.

Written by the indexing model from the issue text.