feat: migrate frontend to Astro + expand AI moderation + backend admin/runtime config

Frontend:
- migrate from Vite to Astro (astro.config.mjs, pages/, layouts/)
- add admin panel, settings page, command palette, error boundary
- refactor App.tsx, MascotChatbot, Sidebar, Header, DashboardLayout
- update API client, WebSocket, auth, dashboard features

Backend:
- add admin module and config routes
- refactor middlewares, Redis connection, WebSocket server/bridge
- add runtime config loader

Discord Gateway:
- refactor AI moderation: circuit breaker, concurrency limiter, fallback processor
- add media analysis client, Seaxng search, user profile learner
- add new drizzle migration

Shared:
- extend database schema, add new config fields

services/frontend/src/widgets/mascot/MascotImage.tsx

@@ -38,6 +38,7 @@ export function MascotImage({
   const sizeClass = sizeMap[size];
   const chatSizeClass = chatSizeMap[size];
   const [isVisible, setIsVisible] = useState(false);
+  const [imgError, setImgError] = useState(false);
 
   useEffect(() => {
     if (showChat && chatMessage) {
@@ -51,13 +52,20 @@ export function MascotImage({
 
   return (
     <div className="relative inline-block">
-      <motion.img
-        src="https://raw.githubusercontent.com/IMPHNEN/imphnen-frontend-service/develop/apps/dimentorin/public/image/mascot-1.png"
-        alt="Mascot"
-        className={`object-contain drop-shadow-md ${sizeClass} ${className}`}
-        whileHover={{ scale: 1.05 }}
-        transition={{ type: "spring", stiffness: 300, damping: 30 }}
-      />
+      {imgError ? (
+        <div className={`flex items-center justify-center ${sizeClass} bg-muted/30 rounded-xl`}>
+          <MessageCircle className="h-6 w-6 text-muted-foreground/50" />
+        </div>
+      ) : (
+        <motion.img
+          src="https://raw.githubusercontent.com/IMPHNEN/imphnen-frontend-service/develop/apps/dimentorin/public/image/mascot-1.png"
+          alt="Mascot"
+          className={`object-contain drop-shadow-md ${sizeClass} ${className}`}
+          whileHover={{ scale: 1.05 }}
+          transition={{ type: "spring", stiffness: 300, damping: 30 }}
+          onError={() => setImgError(true)}
+        />
+      )}
 
       {/* Floating Chat Bubble */}
       {isVisible && chatMessage && (
@@ -72,7 +80,7 @@ export function MascotImage({
             {/* Chat bubble */}
             <div className="bg-primary/90 text-primary-foreground rounded-xl px-4 py-2.5 shadow-lg backdrop-blur-sm border border-primary/30">
               <div className="flex items-start gap-2">
-                <MessageCircle className="h-4 w-4 shrink-0 mt-0.5 text-white/80" />
+                <MessageCircle className="h-4 w-4 shrink-0 mt-0.5 text-primary-foreground/80" />
                 <p className="text-xs leading-relaxed font-medium line-clamp-3">
                   {chatMessage}
                 </p>