PM-5966: Limit copilot history to completed and cancelled challenges

[jmgasper]

Copilot profile history, badge counts, and track totals included draft and active challenges even though fulfillment used only terminal outcomes. Filter the shared Copilot query to completed and cancelled challenges, following the clarification in PM-5966. The reported example now displays 5 challenges (3 completed + 2 cancelled) with 60% fulfillment; its 2 drafts and active post-mortem challenge are excluded.

Client-request cancellations remain in history and track totals and are excluded from fulfillment failures. Update the service documentation and API contract, and add PostgreSQL regression coverage for the clarified behavior.

Validation:

• pnpm lint and pnpm build passed using the pinned Node 26.5.1.
• 14 focused tests passed: 7 service unit tests and 7 regressions executing the service SQL against an isolated PostgreSQL 16 database.
• Regression scenarios cover the QA example, all non-terminal and cancellation statuses, client-only cancellations, 99.5% fulfillment, private challenge filtering, duplicate assignments, and Reviewer history.
• Swagger YAML parsed successfully and git diff --check passed.