F4: extract the reindex button `loading` predicate into a pure, unit-tested
`isReindexButtonLoading({ mutationPending, deadline, status })` next to the
other reindex helpers, replacing the inline JSX expression. Covers the
load-bearing post-cap case (deadline nulled, reindexing stale-true -> not
loading) plus mutationPending, active-run, and finished cases.
F5: rewrite the `useAiSettingsQuery` poll comment to match the actual
`nextReindexPollInterval` stop condition (continues while reindexing===true OR
within deadline and not fully indexed; stops only when reindexing===false &&
indexed>=total, or the deadline cap) instead of the stale "until indexed===total".
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>