feat(ollama): add availability check before model operations

Add `ensureOllamaAvailable` function to lib/ollama.ts for checking and waiting for Ollama server health with configurable timeout.

Integrate the check in GET /api/ollama/models route with 3s timeout to prevent UI blocking, and in POST /api/ollama/pull route with 20s timeout to ensure availability before pulling models.

Update ChatContainer to always render ModelDropdown for better UX when no model is selected.

tsconfig.json

@@ -1,7 +1,11 @@
 {
   "compilerOptions": {
     "target": "ES2017",
-    "lib": ["dom", "dom.iterable", "esnext"],
+    "lib": [
+      "dom",
+      "dom.iterable",
+      "esnext"
+    ],
     "allowJs": true,
     "skipLibCheck": true,
     "strict": true,
@@ -19,7 +23,9 @@
       }
     ],
     "paths": {
-      "@/*": ["./*"]
+      "@/*": [
+        "./*"
+      ]
     }
   },
   "include": [
@@ -28,7 +34,11 @@
     "**/*.tsx",
     ".next/types/**/*.ts",
     ".next/dev/types/**/*.ts",
-    "**/*.mts"
+    "**/*.mts",
+    ".next\\dev/types/**/*.ts",
+    ".next\\dev/types/**/*.ts"
   ],
-  "exclude": ["node_modules"]
+  "exclude": [
+    "node_modules"
+  ]
 }