fix(web): poll agent runs awaiting PR events

[AnxForever]

What & why

Keep the incident detail query polling while an agent run is in awaiting_events. PR comments, merges, and closes can resume this durable state, so stopping the poll left status and transcript updates stale until a manual refresh.

Fixes #398

How to test

• pnpm --filter @superlog/web test
• pnpm typecheck
• pnpm exec biome check apps/web/src/incidents/agent-run-polling.ts apps/web/src/incidents/agent-run-polling.test.ts

AI assistance

• None
• Used AI for: reproducing the polling-state mismatch, drafting the focused fix, and adding the regression test

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would change existing behavior)
• Documentation
• Tests only
• Refactor / cleanup

Checklist

• pnpm typecheck passes
• pnpm lint passes (current main has unrelated existing Biome diagnostics; the changed files pass targeted Biome checks)
• pnpm format has been run on changed files
• Added or updated tests where it makes sense
• Branch is up to date with main
• PR title follows the area-prefix style for the area being changed
• Read CONTRIBUTING.md

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Summary by cubic

Keep incident detail polling active while an agent run is in awaiting_events. This lets PR comments, merges, or closes resume the run and update status/transcript without a manual refresh, with a regression test added to cover the state.

^{Written for commit 889816f. Summary will update on new commits.}

[superlog-app]

Observability review

All clear — no observability concerns found.

All signal, no noise. Ship it!

[cubic-dev-ai]

No issues found across 2 files

_{Re-trigger cubic}