chore(config): pin @types/bun, tighten TypeScript strictness, and refactor config logic

- Pin `@types/bun` to `^1.3.14` for reproducible builds instead of using `latest`
- Update `tsconfig.json` with stricter type-checking flags and reorganize compiler options
- Refactor `initConfig` to DRY up the model default logic and add a null guard before process exit

src/config/index.ts

@@ -23,17 +23,20 @@ export async function initConfig(old: AppConfig | null): Promise<AppConfig> {
   if (isCancel(baseURL)) process.exit(1);
 
   const models = await getModels(baseURL);
+  const initialValue = models.includes(old?.model ?? "")
+    ? old?.model
+    : models[0];
   const model = await autocomplete({
     message: "Choose a default model:",
-    initialValue: models.includes(old?.model ?? "") ? old?.model : models[0],
-    placeholder: models.includes(old?.model ?? "") ? old?.model : models[0],
+    initialValue,
+    placeholder: initialValue ?? "Start typing...",
     options: models.map((model) => ({ value: model })),
     validate: (value) =>
       models.includes(typeof value === "string" ? value : "")
         ? undefined
         : `Unable to find model "${value}"`,
   });
-  if (isCancel(model)) process.exit(1);
+  if (!model || isCancel(model)) process.exit(1);
 
   const config = { baseURL, model } satisfies AppConfig;