Retire the summary hover E2E spec pinned to removed surfaces (#2722)

Deletes the quarantined
`tests/integration/tests/48-summary-hover-selection.spec.ts` and its
`QUARANTINED_SPECS` entry.

None of its nine tests could pass against the current app. Each one
opens `/workloads` or `/storage`, which now show Page Not Found, or
`/infrastructure`, which redirects to the first platform page. Each then
waits for a `workloads-summary`, `infrastructure-summary` or
`storage-summary` card that no longer renders.

The storage pool-group pin test was the only candidate for a port to
`/proxmox/storage?group=node`. Checked against the live page, a
group-header click there collapses the group as it pins it. In that run
the table went from 17 to 14 rows and showed 0 pinned member rows. The
test expects the row count unchanged and every member pinned. It also
asserts summary chart series counts, and those charts no longer exist.
The pin behaviour that still works (hover preview, `summaryGroup`,
pinned emphasis after expanding, Clear selection) is already covered in
`Storage.test.tsx`.

Tier ledger check (`check-e2e-tiering.mjs`, run on pulse-dev):
- origin/main: passes, 102 spec files, 3 quarantined
- this branch: passes, 101 spec files, 2 quarantined, with stable and
probation test counts unchanged (366 / 553)
- spec deleted but ledger entry kept: fails with `QUARANTINED_SPECS has
unknown specs: 48-summary-hover-selection.spec.ts`

tests/integration/e2e-tiering.mjs

@@ -10,7 +10,6 @@ export const QUARANTINED_SPECS = [
   // spec turns that open bug into a permanent red.
   '**/03-multi-tenant.spec.ts',
   '**/47-inline-selection-scroll-stability.spec.ts',
-  '**/48-summary-hover-selection.spec.ts',
 ];
 
 /**