fix: in-flight guards on loadData/loadConfig, remove duplicate loadConfig

Concurrent calls from rapid reloads or rapid saves could pile up,
each writing state on completion and potentially re-triggering more loads.
Guards ensure only one load is in flight at a time; extra calls are dropped.

src/routes/admin/+page.svelte

@@ -40,15 +40,6 @@
   let configError = $state<string | null>(null);
   let configSuccess = $state<string | null>(null);
 
-  async function loadConfig() {
-    const res = await fetch(`${api}/config`);
-    if (!res.ok) return;
-    const c = await res.json();
-    configYoloLabel = c.yoloLabel ?? 'YOLO mode';
-    configYoloDescription = c.yoloDescription ?? '(cross-group conversions)';
-    configYoloVisibility = c.yoloVisibility ?? 'auto';
-  }
-
   async function saveConfig() {
     configSaving = true;
     configError = null;
@@ -227,16 +218,39 @@
   }
 
   // ── Load data ────────────────────────────────────────────────────────────────
+  let loadDataInFlight = false;
   async function loadData() {
-    const [res, gres] = await Promise.all([
-      fetch(`${api}/units`),
-      fetch(`${api}/groups`)
-    ]);
-    if (!res.ok) return;
-    const units: Unit[] = await res.json();
-    const groups: Group[] = gres.ok ? await gres.json() : [];
-    unitsData = { units, groups };
-    expandedGroups = new Set([...expandedGroups, ...groups.map((g) => g.id)]);
+    if (loadDataInFlight) return;
+    loadDataInFlight = true;
+    try {
+      const [res, gres] = await Promise.all([
+        fetch(`${api}/units`),
+        fetch(`${api}/groups`)
+      ]);
+      if (!res.ok) return;
+      const units: Unit[] = await res.json();
+      const groups: Group[] = gres.ok ? await gres.json() : [];
+      unitsData = { units, groups };
+      expandedGroups = new Set([...expandedGroups, ...groups.map((g) => g.id)]);
+    } finally {
+      loadDataInFlight = false;
+    }
+  }
+
+  let loadConfigInFlight = false;
+  async function loadConfig() {
+    if (loadConfigInFlight) return;
+    loadConfigInFlight = true;
+    try {
+      const res = await fetch(`${api}/config`);
+      if (!res.ok) return;
+      const c = await res.json();
+      configYoloLabel = c.yoloLabel ?? 'YOLO mode';
+      configYoloDescription = c.yoloDescription ?? '(cross-group conversions)';
+      configYoloVisibility = c.yoloVisibility ?? 'auto';
+    } finally {
+      loadConfigInFlight = false;
+    }
   }
 
   onMount(() => { loadData(); loadConfig(); });