Improve error logging observability for created_via_invite rollout

[Copilot]

Summary

Addresses feedback on #1602: log all initial insert errors before retry decisions to improve observability during created_via_invite column rollout.

Pattern change:

// Before: only logged when retrying
if (isMissingCreatedViaInviteColumnError(error)) {
  cloudlog({ message: 'retrying', error })
}

// After: always log initial error, separate retry decision
if (error) {
  cloudlog({ message: 'initial insert error', error })
}
if (isMissingCreatedViaInviteColumnError(error)) {
  cloudlog({ message: 'retrying without column' })
}

This ensures visibility into unexpected errors that might be masked by successful retries, even when the missing column error is not the root cause.

Modified locations:

• ensurePublicUserRowExists: lines 150-156
• accept_invitation handler: lines 456-462

Test plan

• Existing test suite validates no functional changes
• Logs will be monitored during production rollout

Screenshots

N/A - backend logging change only

Checklist

• My code follows the code style of this project and passes
  bun run lint:backend && bun run lint.
• My change requires a change to the documentation.
• I have updated the documentation
  accordingly.
• My change has adequate E2E test coverage.
• I have tested my code manually, and I have provided steps how to reproduce
  my tests

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Copilot]

Pull request overview

Improves observability during the created_via_invite backward-compatible column rollout by ensuring initial insert errors are always logged before any retry/fallback behavior in the invitation acceptance flow.

Changes:

• Added “initial insert error” logging before retry decisions in ensurePublicUserRowExists.
• Added “initial user insert error” logging before retry decisions in the main accept_invitation handler.
• Removed the error object from the “retrying without column” log line to avoid duplicating the same error in multiple log events.

[Copilot]

These logs are recording insert failures; consider using cloudlogErr (stderr) instead of cloudlog so error-level logs can be filtered/alerted consistently across runtimes.

[Copilot]

This is logging an actual insert error; consider emitting it via cloudlogErr (stderr) instead of cloudlog to keep error logs consistent and easier to detect in production logging pipelines.