style: make settings page wider for better prompt editing

src/pages/SettingsPage.tsx

@@ -163,7 +163,7 @@ export function SettingsPage() {
   return (
     <div className="min-h-screen">
       <header className="sticky top-0 z-20 bg-bg/70 backdrop-blur border-b border-border">
-        <div className="max-w-md mx-auto px-4 h-14 flex items-center gap-2">
+        <div className="max-w-3xl mx-auto px-4 h-14 flex items-center gap-2">
           <button
             type="button"
             onClick={() => navigate("/")}
@@ -176,7 +176,7 @@ export function SettingsPage() {
         </div>
       </header>
 
-      <main className="max-w-md mx-auto px-4 mt-16">
+      <main className="max-w-3xl mx-auto px-4 mt-16">
         <div className="card p-6 space-y-6">
           <section>
             <h2 className="text-sm font-semibold text-fg mb-3 flex items-center gap-2">
@@ -376,7 +376,7 @@ export function SettingsPage() {
                 </select>
 
                 <textarea
-                  className="input w-full min-h-[300px] text-xs font-mono p-3 leading-relaxed"
+                  className="input w-full min-h-[500px] text-xs font-mono p-3 leading-relaxed"
                   value={editingPrompts[activePromptTab]}
                   onChange={(e) => handlePromptChange(e.target.value)}
                   spellCheck={false}