fix(home): $effect-Loop bei sort=viewed via untrack

Der Profile-Switch-Refetch-Effect las allLoading in der sync tracking-
Phase. Der await fetch beendete die Sync-Phase, das finale
allLoading = false im finally lief ausserhalb → wurde als externer
Write interpretiert → Effect rerun → naechster Fetch → Endlosschleife.

2136 GETs auf /api/recipes/all?sort=viewed in 8s beobachtet.

Fix: nur profileStore.active bleibt tracked (der tatsaechliche
Trigger). allSort/allLoading werden in untrack() gelesen — die Writes
auf allLoading im finally triggern damit keinen Effect-Rerun mehr.

Verifiziert lokal: 1 Request statt 2000+ bei mount mit allSort=viewed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/routes/+page.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-  import { onMount, tick } from 'svelte';
+  import { onMount, tick, untrack } from 'svelte';
   import { page } from '$app/stores';
   import { CookingPot, X, ChevronDown } from 'lucide-svelte';
   import { slide } from 'svelte/transition';
@@ -235,12 +235,17 @@
   // profiles, refetch with the new profile_id so the list reflects what
   // the *current* profile has viewed. Other sorts are profile-agnostic
   // and don't need this.
+  //
+  // Only `profileStore.active` must be a tracked dep. `allSort` /
+  // `allLoading` are read inside untrack: otherwise the `allLoading = false`
+  // write in the fetch-finally would re-trigger the effect and start the
+  // next fetch → endless loop.
   $effect(() => {
-    const active = profileStore.active;
+    // eslint-disable-next-line @typescript-eslint/no-unused-expressions
+    profileStore.active;
+    untrack(() => {
       if (allSort !== 'viewed') return;
       if (allLoading) return;
-    // Re-fetch the first page; rehydrate would re-load the previous
-    // depth, but a sort-context change should reset to page 1 anyway.
       void (async () => {
         allLoading = true;
         try {
@@ -253,10 +258,9 @@
         } finally {
           allLoading = false;
         }
-      // 'active' is referenced so $effect tracks it as a dep:
-      void active;
       })();
     });
+  });
 
   // Sync current query back into the URL as ?q=... via replaceState,
   // without spamming the history stack. Pushing a new entry happens only