fix(ModelPicker): prevent useInput during model loading to avoid yoga-layout WASM error

Error:

```
⠋ Loading models...

Mode: Safe (Shift+Tab to toggle) ❖ Model: gemma4:latest
wasm://wasm/000460e2:1

RuntimeError: memory access out of bounds
    at wasm://wasm/000460e2:wasm-function[215]:0xd5ef
    at wasm://wasm/000460e2:wasm-function[185]:0xcf8c
    at X.getComputedWidth (file:///code-ollama/node_modules/yoga-layout/dist/binaries/yoga-wasm-base64-esm.js:33:52)
    at renderer (code-ollama/node_modules/ink/src/renderer.ts:50:37)
    at onRender (code-ollama/node_modules/ink/src/ink.tsx:533:48)
    at debounce$1.edges.edges (file:///code-ollama/node_modules/es-toolkit/dist/compat/function/debounce.mjs:18:23)
    at invoke (file:///code-ollama/node_modules/es-toolkit/dist/function/debounce.mjs:8:18)
    at onTimerEnd (file:///code-ollama/node_modules/es-toolkit/dist/function/debounce.mjs:15:13)
    at Timeout._onTimeout (file:///code-ollama/node_modules/es-toolkit/dist/function/debounce.mjs:26:13)
    at listOnTimeout (node:internal/timers:605:17)
```

Cause:

The yoga-layout WASM memory error occurs because the `useInput` hook in
ModelPicker was active even while models were loading. When users
pressed navigation keys during the "Loading models..." Spinner state, it
triggered re-renders that conflicted with yoga-layout's layout
calculations, causing the memory access out of bounds error.

Fix:

Added `isActive: Boolean(options.length)` to the useInput hook to only register
keyboard input handling after models are loaded. This prevents the
Spinner animation from being interrupted by keyboard events.

Author: remarkablemark

src/components/ModelPicker.tsx

@@ -18,17 +18,16 @@ export function ModelPicker({ currentModel, onSelect, onClose }: Props) {
   const [error, setError] = useState<string | null>(null);
 
   // close select prompt if current model is chosen
-  // eslint-disable-next-line @typescript-eslint/no-misused-promises
-  useInput(async (_input, key) => {
-    if (!options.length) {
-      return;
-    }
-
-    if (key.return) {
-      await time.tick();
-      onClose();
-    }
-  });
+  useInput(
+    // eslint-disable-next-line @typescript-eslint/no-misused-promises
+    async (_input, key) => {
+      if (key.return) {
+        await time.tick();
+        onClose();
+      }
+    },
+    { isActive: Boolean(options.length) },
+  );
 
   useEffect(() => {
     async function load() {