Three frontend findings (medium):
1. **`hooks.server.ts` didn't chain client-disconnect into the upstream
fetch.** Closing an admin tab left the backend's `broadcast::Receiver`
+ spawned tokio task running until next backend restart. Listen for
`event.request.signal.abort` and forward to the timeout controller.
2. **`admin/analysis/+page.svelte` missing visibility/pagehide/pageshow
handlers.** Mobile Safari throttles SSE in background tabs; bfcache
leaves a dead connection on back-nav. Apply the close/open-stream
pattern from `admin/crawler/+page.svelte`.
3. **`loadCoverage` had no AbortController.** Debounced search
keystrokes raced. Per-loader controller plumbed through
`getAnalysisMangaCoverage`.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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