feat(web): add /admin/requests approval queue with override modal

Pending/Approved/Completed/Rejected tabs (active count only). Override modal
collapsed by default; reject modal with notes textarea. Lidarr-unreachable
toast surfaces sync-Approve failures. Cancel buttons in both modals are
Pewter ghost; Reject/Confirm reject use Bronze (the design system reserves
Oxblood for irreversible actions like Disconnect).

web/src/routes/admin/requests/+page.svelte

@@ -8,7 +8,6 @@
     approveRequest,
     rejectRequest
   } from '$lib/api/admin';
-  import { qk } from '$lib/api/queries';
   import StatusPill from '$lib/components/StatusPill.svelte';
   import type { LidarrRequest, LidarrRequestKind, LidarrRequestStatus } from '$lib/api/types';
 
@@ -348,7 +347,7 @@
       <div class="mt-5 flex justify-end gap-2">
         <button
           type="button"
-          class="rounded-md bg-action-secondary px-3 py-1.5 text-sm text-text-primary"
+          class="rounded-md border border-border px-3 py-1.5 text-sm text-text-secondary hover:text-text-primary"
           onclick={cancelOverride}
         >
           Cancel
@@ -400,14 +399,14 @@
       <div class="mt-5 flex justify-end gap-2">
         <button
           type="button"
-          class="rounded-md bg-action-secondary px-3 py-1.5 text-sm text-text-primary"
+          class="rounded-md border border-border px-3 py-1.5 text-sm text-text-secondary hover:text-text-primary"
           onclick={cancelReject}
         >
           Cancel
         </button>
         <button
           type="button"
-          class="inline-flex items-center gap-1 rounded-md bg-action-destructive px-3 py-1.5 text-sm text-text-primary"
+          class="inline-flex items-center gap-1 rounded-md bg-action-secondary px-3 py-1.5 text-sm text-text-primary"
           onclick={() => confirmReject(rejectRow!)}
         >
           <X size={14} strokeWidth={2} />