config_reader.py now merges environment variables (AI_PROVIDER,
LMSTUDIO_BASE_URL, LMSTUDIO_API_KEY, LMSTUDIO_MODEL, OLLAMA_*,
ANTHROPIC_*) on top of the JSON config file, so the dev .env file
can pin the AI connection without writing to the shared config volume.
docker-compose.dev.yml loads features/doc-service/.env (gitignored)
into the doc-service container so the token is never committed.
.env.example updated with all supported override variables and comments.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
