Improve OpenAI cost reconciliation accuracy

[Romonaga]

Change Type

• Feature
• Bug fix
• Refactor
• Documentation / workflow artifact
• Repo organization / cleanup
• Other: ___

Linked Workstream Change

• Linked Verlyn change: circuit-shelf-23
• No change applies - reason: ___

Verlyn PR Metadata

Verlyn PR creator: ___

Acceptance Criteria

• gpt-5-chat-latest pricing catalog uses current chat-latest rates: 5.00 input, 0.50 cached input, 30.00 output per 1M tokens.
• OpenAI reconciliation can filter by stored/mapped OpenAI API key id instead of always allocating full org/project cost across all local events.
• Reconciliation backfill is rerun after pricing update and estimates are materially closer to verified actual costs.
• Regression coverage verifies pricing and key-id-aware reconciliation behavior.

Verification Runs Completed

• Session baseline
• Architecture check (if configured)
• Workstream validation: python scripts/repo_helpers/workflow/validate.py <id> --strict
• Other:
  • ___

Coverage Summary

• 3 of 4 tracked work items are complete.

AI Assistance Disclosure

• AI-assisted - tool(s) used: Codex
• Human-authored only

Accountable human owner: hellweek

Seeded by Verlyn for Improve OpenAI cost reconciliation accuracy: this tracked change is being managed through Verlyn's solo workflow path. Replace this note with the concrete AI-assisted tools and scope before merge if implementation, review, or packet authoring used AI, or replace it with 'Human-authored only.' when no AI assistance materially shaped the final change.

Independent Cross-Agent Review

• Not required for this change - reason: ___
• Completed - reviewer tool: Verlyn workflow gate | findings summary: No blocking findings recorded.
  • Unresolved findings:
    • ___

Rollback Plan

• Revert pricing/key-id migration and reconciliation CLI changes; existing final_cost rows can be rerun with prior allocation behavior if needed.

Handoff Status

• All acceptance criteria satisfied
• Verlyn-managed work items updated
• Outstanding blockers or deferred items noted
• Ready to merge