- Merge all configuration into settings.py with PRY_* env var prefix.
- Add legacy env aliases (PROXY_URL, TOR_ENABLED, MAX_RETRIES, etc.) for migration.
- Load and persist runtime overrides from JSON config file (default /app/config.json).
- Update scraper.py, deps.py, routers/config.py to use unified settings.
- Add resolved_proxy_chain and resolved_proxy_url properties.
- Replace tests/test_mconfig.py with tests/test_settings.py (9 tests).
- Update .env.example with new PRY_* options.
- All 500 tests pass; ruff clean.
