feat: report next UI patrol schedule evidence

[wlsdks]

Summary

• Add schedule_cron and next_expected_schedule_utc to pending evidence:ui-patrol output.
• Document the new fields in the backlog, 9.5 plan, goal audit, and task log.
• Keep scheduled_ui_patrol pending until a real schedule event and 9-png artifact exist.

Effect Check

• corepack pnpm evidence:ui-patrol now tells operators when to re-check the external cron event.
• promptlane_95_quality remains pending with the same blockers.
• This avoids rerunning unrelated local UI checks while waiting for GitHub Actions schedule evidence.

Verification

• RED: corepack pnpm vitest run src/packaging/plugin-files.test.ts --testNamePattern "scheduled ui-patrol evidence" failed while next_expected_schedule_utc and schedule_cron were absent.
• GREEN: same focused test passed after implementation.
• corepack pnpm --silent evidence:ui-patrol
• corepack pnpm --silent evidence:quality | node -e '...'
• corepack pnpm test
• corepack pnpm lint
• corepack pnpm build
• node scripts/ui-patrol-evidence.mjs | sed -n '1,30p'
• corepack pnpm pack:dry-run
• git diff --check