Retire mode-run authority from discussion events

[adrianwebb]

Outcome

Retire the old mode-run field from governed discussion events while preserving assignment attribution.

Work authority

• Work item / Issue: Retire the old mode-run field from discussion content #26; Platform #520.
• Proposal / decision: Existing accepted authority unchanged; integration only.
• Assignment / checkpoint: September 30 staging-integration instruction.
• Actor: Codex.
• Human authority: @adrianwebb.
• Agent / capacity provider: N/A — local integration.
• Exact base ref: staging dd4a7f2.
• Exact head ref: codex/retire-discussion-mode-run 8385d22.

Contributor mode (select one):

• Human-authored
• Agent-assisted under human authority
• Agent-authored under human authority

Plan

Integrate existing field removal, add focused parsed-output regression, run required Actions, return clean staging.

Changes and commits

8385d22: removes modeRunId from the existing discussion-event schema; regression preserves assignmentId and rejects exposing retired authority in parsed output. No new schema or storage.

Verification

111 existing tests/32 files passed; new focused content suite three tests passed, ownership checks passed. Required Actions pending. No full golden claim.

Risk and rollback

One retired optional field is no longer projected. Revert through checked staging PR if needed; no data purge, credentials or runtime cutover.

Completion summary

Implementation verified locally and ready for checked staging integration.

Submission checklist

• The change is bounded to the stated work item and target repository.
• Exact base and head refs are recorded and the branch is ready for review.
• Verification and compatibility evidence are recorded above.
• No plaintext secrets, credentials, machine state, or unrelated residue are included.
• Plan, status, commits, and completion summary form a complete durable record.
• Rollback or recovery steps are documented and executable.