MediaClean 0.1.5 QA patch.\n\nFixes:\n- Scans now group duplicates only from the current scan roots, preventing stale duplicate groups from previously scanned folders from appearing in later scans.\n- Malformed quarantine query parameters now return JSON 400 responses instead of dropping the connection.\n\nVerification:\n- pytest: 17 passed\n- node --check mediaclean/static/app.js\n- Python compileall\n- Playwright QA smoke for Settings, scan scope, group review, quarantine, restore, protected-folder skip, Activity, diagnostics, and bad API params\n- Developer ID signed, notarized, stapled, and Gatekeeper accepted\n\nSHA-256: 0dbe660a4f7a37e3b39242bbc6726190db49fc9730d545729c19c752aae33ffc