feat(seer): Poll live autofix run status on overview

[NicoHinderling]

Polls live Autofix run status on the overview page so cards show a "Working…" spinner while a run is actively processing, and so a card moves sections (e.g. a PR merged directly on GitHub → "Merged") within ~10s — even when no run is running.

How

• The overview hook now runs a light expand=status poll every POLL_INTERVAL (10s), alongside the enriched (scmInfo/issueStats/status) request. The poll pauses when the tab is hidden.
• Each poll overlays the freshest per-run status onto the rendered cards (by seerRunId), so spinners update without re-fetching enrichment.
• A (seerRunId, milestone) section signature is computed from each poll; when it changes (a run moved section, or appeared/disappeared) the enriched request is silently refetched, so badges/counts and bucketing stay consistent.
• OverviewAction renders a Working… spinner when a run's status is processing.

Notes

• Stacked on the backend PR feat(seer): Add status expand for live autofix run status #122190 (status expand) and blocked on that backend deploying — the poll is a no-op (status: null) until the endpoint ships.
• Out of scope: live "checks passed"/"approved" badges — those are GitHub-sourced enrichment and need their own webhook mechanism, independent of this poll.
• Follow-up (v2): swap the poll transport for Conduit/SSE once it is production-ready, keeping polling as the fallback.

[github-actions]

📊 Type Coverage Diff

Metric	Before	After	Delta
Coverage	94.36%	94.36%	±0%
Typed	134,662	134,689	🟢 +27
Untyped	8,046	8,047	🔴 +1

🔍 1 new type safety issue introduced

Type assertions (as) (1 new)

File	Line	Detail
static/app/views/seerWorkflows/overview/useAutofixOverview.ts	67	as AutofixOverviewResponse['runsByMilestone'] — Object.fromEntries( Object.entries(base.runsByMilestone).map(([milestone, runs]…

This is informational only and does not block the PR.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

There are 2 total unresolved issues (including 1 from previous review).

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit de70d94. Configure here.}

[linear-code]

AIML-3342