Improve model status indicators and tune timeouts

Green/red emoji circles replace Unicode symbols for at-a-glance model
readiness. Increase connect timeouts (10→30s) for cold model loading,
warm timeout (120→300s) for large models, and pull timeout (600→1800s)
to match route-level limit. Show error toast on SSE reconnection failure
instead of silently recovering.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/ModelSelector.vue

@@ -49,7 +49,7 @@ onMounted(async () => {
       :key="m.name"
       :value="m.name"
     >
-      {{ isHot(m.name) ? "\u2B24 " : "\u25CB " }}{{ m.name }}
+      {{ isHot(m.name) ? "🟢 " : "🔴 " }}{{ m.name }}
     </option>
   </select>
 </template>

frontend/src/stores/chat.ts

@@ -239,6 +239,10 @@ export const useChatStore = defineStore("chat", () => {
 
     // Recovery fallback: re-fetch conversation from DB
     if (!gotDone && currentConversation.value?.id === convId) {
+      useToastStore().show(
+        "Connection lost — response may be incomplete",
+        "error",
+      );
       try {
         await fetchConversation(convId);
       } catch {