fix(recipe): View-Beacon ueber \$effect statt onMount

Live-Test auf kochwas-dev: bei Hard-Reload/Cold-Start (nicht SPA-Click)
landete kein view-Eintrag in der DB. Ursache: Recipe-Page-onMount
feuert vor Layout-onMount, profileStore.load() laeuft aber im Layout-
onMount und macht erst danach einen async fetch — zum Zeitpunkt des
Beacons war profileStore.active noch null.

Loesung: Beacon im \$effect, das auf profileStore.active reagiert.
viewBeaconSent-Flag verhindert duplicate POSTs wenn der User waehrend
der Page-Lifetime das Profil wechselt — der ursprueglich getrackte
Profil-View bleibt der "richtige" fuer dieses Page-Open.

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

src/routes/recipes/[id]/+page.svelte

@@ -356,19 +356,27 @@
     };
     document.addEventListener('visibilitychange', onVisibility);
 
-    // Track view per active profile (fire-and-forget). Skipped when no
-    // profile is active — we'd just be writing rows nobody can sort against later.
-    if (profileStore.active) {
-      void fetch(`/api/recipes/${data.recipe.id}/view`, {
-        method: 'POST',
-        headers: { 'content-type': 'application/json' },
-        body: JSON.stringify({ profile_id: profileStore.active.id })
-      });
-    }
-
     return () => document.removeEventListener('visibilitychange', onVisibility);
   });
 
+  // Track view per active profile (fire-and-forget). Lives in $effect, not
+  // onMount, because profileStore.load() runs from layout's onMount and the
+  // child onMount fires first — at mount time profileStore.active is still
+  // null on cold loads. The effect re-runs once active populates, the
+  // viewBeaconSent flag prevents duplicate POSTs on subsequent profile
+  // switches within the same page instance.
+  let viewBeaconSent = $state(false);
+  $effect(() => {
+    if (viewBeaconSent) return;
+    if (!profileStore.active) return;
+    viewBeaconSent = true;
+    void fetch(`/api/recipes/${data.recipe.id}/view`, {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({ profile_id: profileStore.active.id })
+    });
+  });
+
   onDestroy(() => {
     void releaseWakeLock();
   });