fix(frontend): /me history goes stale under Activity (audit finding 1)

[Shaan-alpha]

Finding 1 from the Activity audit in #59. Same root cause as that PR, different component and a different symptom — this one is data correctness rather than cosmetics.

The bug

HistoryGrid seeds items from the analyses prop with useState. That used to be safe: navigating away unmounted /me, so returning remounted the component and reseeded it from the fresh server payload.

Under cacheComponents: true the App Router hides /me behind React's <Activity> and keeps it alive for up to 3 routes. The seed sticks. So: open /me, go analyse someone, save them, come back — the new analysis is not in your history. The server sent it; the component ignored it.

Reproduced before fixing: render with one row, hide, re-show with two rows, and the second row never appears.

The fix

Resync on the server list's content, not its identity. A fresh server render hands over a new array on every pass, so resetting on identity would wipe an in-flight undo for no reason — there is a regression test for exactly that.

This is React's documented "adjusting state when a prop changes" pattern: a plain render-time computation, no useEffect and no extra paint.

Two details worth calling out:

• The pending row stays optimistically removed across a resync. Its DELETE has not been sent yet, so the server still legitimately lists it; naively resyncing would make a deleted card flicker back while its own undo toast is still on screen. Covered by a test.
• orderRef became state. The resync rewrites it, and writing a ref during render is not allowed — react-hooks/refs caught this, which is how it was found rather than shipped.

Tests

Four new cases alongside the existing delete/undo pair, all driving a real <Activity> hide→show cycle:

• picks up an analysis saved elsewhere (failed before the fix)
• drops an analysis deleted elsewhere (failed before the fix)
• a resync does not resurrect a card inside its undo window (failed before the fix)
• does not reset the list when the prop identity changes but content does not (passed before, guards the fix from over-correcting)

Verification

vitest run 77 passed / 23 files, tsc --noEmit clean, eslint src clean.

Merge order

Independent of #59 and #60 — no shared files. CI here will stay red until #60 merges: main is currently red from a fixture time bomb unrelated to any of this.

Findings 2 and 3 from the audit (badge popover escaping the Activity boundary; badge trigger not exposed as a button) are still unfixed and documented in docs/PROGRESS_LOG.md.

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