fix: add error handling for share queries and filter fetch retries

[Movm]

Summary

• Gracefully handle getUserShares failures in the share controller by returning an empty result instead of crashing
• Add retry logic with cooldown (max 3 retries, 30s cooldown) to fetchFilterValues in the notebook store to prevent infinite fetch loops on failure
• Add apps/api/services/remotion/out/ to .gitignore

Test plan

• Verify share image endpoint returns empty array when DB query fails
• Verify filter fetching stops retrying after 3 failures
• Verify filter fetching resumes after cooldown period
• Verify successful filter fetch clears previous error state