feat: poll in-flight requests on native + refresh after submit (#369)

Native RequestsViewModel gains poll-while-approved (silent reloads, paused
when nothing in-flight) for parity with the web auto-poll, and the SSE
collector now reloads silently instead of flashing the loading spinner.
Web discover submit invalidates qk.myRequests() so a new request appears
on /requests immediately.

web/src/routes/discover/+page.svelte

@@ -2,6 +2,8 @@
   import { pageTitle } from '$lib/branding';
   import { createLidarrSearchQuery } from '$lib/api/lidarr';
   import { createRequest } from '$lib/api/requests';
+  import { qk } from '$lib/api/queries';
+  import { useQueryClient } from '@tanstack/svelte-query';
   import DiscoverResultCard from '$lib/components/DiscoverResultCard.svelte';
   import DiscoverTabs from '$lib/components/DiscoverTabs.svelte';
   import ApiErrorBanner from '$lib/components/ApiErrorBanner.svelte';
@@ -12,6 +14,8 @@
     LidarrSearchResult
   } from '$lib/api/types';
 
+  const queryClient = useQueryClient();
+
   // Local input is the source of truth for the discover query — Shell's global
   // SearchInput targets /search, not /discover. We debounce by 250ms before
   // pushing into `debouncedQ`, which is what the query factory observes.
@@ -87,6 +91,8 @@
       const next = new Set(optimisticRequested);
       next.add(r.mbid);
       optimisticRequested = next;
+      // Surface the new request on /requests right away (+ start its poll) (#369).
+      queryClient.invalidateQueries({ queryKey: qk.myRequests() });
     } catch {
       // Swallow for v1: error toasts land in a later UX pass. The card stays
       // in 'requestable' so the user can retry.