- Guard against malformed localStorage values (e.g. "provider/") by validating both parts are non-empty before sending to the server - Only wire settings fallback when both provider AND modelId are explicitly provided, preventing mismatched provider/modelId combos Addresses ISSUE-002 and ISSUE-003 from code quality review. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>