feat(web): wire knowledge pages to real API data (#476)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/web/src/components/knowledge/StatsDashboard.tsx

@@ -2,6 +2,7 @@
 
 import { useEffect, useState } from "react";
 import { fetchKnowledgeStats } from "@/lib/api/knowledge";
+import { MosaicSpinner } from "@/components/ui/MosaicSpinner";
 import Link from "next/link";
 
 interface KnowledgeStats {
@@ -61,13 +62,20 @@ export function StatsDashboard(): React.JSX.Element {
   if (isLoading) {
     return (
       <div className="flex items-center justify-center p-12">
-        <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-blue-500" />
+        <MosaicSpinner size={36} label="Loading statistics..." />
       </div>
     );
   }
 
   if (error || !stats) {
-    return <div className="p-8 text-center text-red-500">Error loading statistics: {error}</div>;
+    return (
+      <div className="p-8 text-center">
+        <p className="font-medium mb-2" style={{ color: "var(--danger)" }}>
+          Error loading statistics
+        </p>
+        <p className="text-sm text-gray-500 dark:text-gray-400">{error}</p>
+      </div>
+    );
   }
 
   const { overview, mostConnected, recentActivity, tagDistribution } = stats;