feat: model switching shows loading spinner, disables input until ready

frontend/src/components/Chat/InputArea.tsx

@@ -23,6 +23,7 @@ export function InputArea() {
   const updateLastAssistant = useAppStore((s) => s.updateLastAssistant);
   const setStreamState = useAppStore((s) => s.setStreamState);
   const resetStream = useAppStore((s) => s.resetStream);
+  const modelLoading = useAppStore((s) => s.modelLoading);
 
   const { state: speechState, available: speechAvailable, startRecording, stopRecording } = useSpeech();
 
@@ -272,7 +273,7 @@ export function InputArea() {
           rows={1}
           className="flex-1 bg-transparent outline-none resize-none text-sm leading-relaxed"
           style={{ color: 'var(--color-text)', maxHeight: '200px' }}
-          disabled={streamState.isStreaming}
+          disabled={streamState.isStreaming || modelLoading}
         />
         {streamState.isStreaming ? (
           <button
@@ -293,7 +294,7 @@ export function InputArea() {
             />
             <button
               onClick={sendMessage}
-              disabled={!input.trim()}
+              disabled={!input.trim() || modelLoading}
               className="p-2 rounded-xl transition-colors shrink-0 cursor-pointer disabled:opacity-30 disabled:cursor-default"
               style={{
                 background: input.trim() ? 'var(--color-accent)' : 'var(--color-bg-tertiary)',

frontend/src/components/CommandPalette.tsx

@@ -1,7 +1,7 @@
 import { useState, useRef, useEffect } from 'react';
 import { Search, Cpu, X, Download, Loader2, Trash2, Check } from 'lucide-react';
 import { useAppStore } from '../lib/store';
-import { pullModel, deleteModel, fetchModels } from '../lib/api';
+import { pullModel, deleteModel, fetchModels, preloadModel } from '../lib/api';
 
 /** Popular models that users can download from the catalogue. */
 const CATALOGUE_MODELS = [
@@ -65,9 +65,25 @@ export function CommandPalette() {
     }
   }, [pullSuccess]);
 
-  const handleSelect = (modelId: string) => {
+  const handleSelect = async (modelId: string) => {
+    const previousModel = selectedModel;
     setSelectedModel(modelId);
     setCommandPaletteOpen(false);
+
+    // Preload the model if switching to a different one
+    if (modelId !== previousModel) {
+      const { setModelLoading, addLogEntry } = useAppStore.getState();
+      setModelLoading(true);
+      addLogEntry({ timestamp: Date.now(), level: 'info', category: 'model', message: `Switching to ${modelId}...` });
+      try {
+        await preloadModel(modelId);
+        addLogEntry({ timestamp: Date.now(), level: 'info', category: 'model', message: `${modelId} loaded` });
+      } catch (e: any) {
+        addLogEntry({ timestamp: Date.now(), level: 'error', category: 'model', message: `Failed to load ${modelId}: ${e.message}` });
+      } finally {
+        setModelLoading(false);
+      }
+    }
   };
 
   const refreshModels = async () => {

frontend/src/components/Sidebar/Sidebar.tsx

@@ -14,6 +14,7 @@ import {
   Sun,
   Moon,
   Monitor,
+  Loader2,
 } from 'lucide-react';
 import { ConversationList } from './ConversationList';
 import { useAppStore } from '../../lib/store';
@@ -29,6 +30,7 @@ export function Sidebar() {
   const selectedModel = useAppStore((s) => s.selectedModel);
   const serverInfo = useAppStore((s) => s.serverInfo);
   const setCommandPaletteOpen = useAppStore((s) => s.setCommandPaletteOpen);
+  const modelLoading = useAppStore((s) => s.modelLoading);
 
   const settings = useAppStore((s) => s.settings);
   const updateSettings = useAppStore((s) => s.updateSettings);
@@ -120,16 +122,29 @@ export function Sidebar() {
             onMouseEnter={(e) => (e.currentTarget.style.background = 'var(--color-bg-tertiary)')}
             onMouseLeave={(e) => (e.currentTarget.style.background = 'var(--color-bg-secondary)')}
           >
-            <Cpu size={14} />
-            <span className="truncate flex-1 text-left" style={{ color: 'var(--color-text)' }}>
-              {selectedModel || serverInfo?.model || 'Select model'}
-            </span>
-            <kbd
-              className="text-[10px] px-1.5 py-0.5 rounded font-mono"
-              style={{ background: 'var(--color-bg-tertiary)', color: 'var(--color-text-tertiary)' }}
-            >
-              ⌘K
-            </kbd>
+            {modelLoading ? (
+              <Loader2 size={14} className="animate-spin" style={{ color: 'var(--color-accent)' }} />
+            ) : (
+              <Cpu size={14} />
+            )}
+            <div className="flex-1 min-w-0">
+              <span className="truncate block text-left" style={{ color: 'var(--color-text)' }}>
+                {selectedModel || serverInfo?.model || 'Select model'}
+              </span>
+              {modelLoading && (
+                <span className="text-[10px] block" style={{ color: 'var(--color-accent)' }}>
+                  Loading model...
+                </span>
+              )}
+            </div>
+            {!modelLoading && (
+              <kbd
+                className="text-[10px] px-1.5 py-0.5 rounded font-mono"
+                style={{ background: 'var(--color-bg-tertiary)', color: 'var(--color-text-tertiary)' }}
+              >
+                ⌘K
+              </kbd>
+            )}
           </button>
 
           {/* Search */}