feat(web): port chat UI — model selector, keybindings, thinking display, styled header

apps/web/src/components/chat/streaming-message.tsx

@@ -1,26 +1,97 @@
 'use client';
 
-/** Renders an in-progress assistant message from streaming text. */
+import { useEffect, useMemo, useState } from 'react';
+
 interface StreamingMessageProps {
   text: string;
+  modelName?: string | null;
+  thinking?: string;
 }
 
-export function StreamingMessage({ text }: StreamingMessageProps): React.ReactElement {
+const WAITING_QUIPS = [
+  'The AI is warming up... give it a moment.',
+  'Brewing some thoughts...',
+  'Summoning intelligence from the void...',
+  'Consulting the silicon oracle...',
+  'Teaching electrons to think...',
+];
+
+const TIMEOUT_QUIPS = [
+  'The model wandered off. Let’s try to find it again.',
+  'Response is taking the scenic route.',
+  'That answer is clearly overthinking things.',
+  'Still working. Either brilliance or a detour.',
+];
+
+export function StreamingMessage({
+  text,
+  modelName,
+  thinking,
+}: StreamingMessageProps): React.ReactElement {
+  const [elapsedMs, setElapsedMs] = useState(0);
+
+  useEffect(() => {
+    setElapsedMs(0);
+    const startedAt = Date.now();
+    const timer = window.setInterval(() => {
+      setElapsedMs(Date.now() - startedAt);
+    }, 1000);
+    return () => window.clearInterval(timer);
+  }, [text, modelName, thinking]);
+
+  const quip = useMemo(() => {
+    if (elapsedMs >= 18_000) {
+      return TIMEOUT_QUIPS[Math.floor((elapsedMs / 1000) % TIMEOUT_QUIPS.length)];
+    }
+    if (elapsedMs >= 4_000) {
+      return WAITING_QUIPS[Math.floor((elapsedMs / 1000) % WAITING_QUIPS.length)];
+    }
+    return null;
+  }, [elapsedMs]);
+
   return (
     <div className="flex justify-start">
-      <div className="max-w-[75%] rounded-xl border border-surface-border bg-surface-elevated px-4 py-3 text-sm text-text-primary">
+      <div
+        className="max-w-[min(78ch,85%)] rounded-3xl border px-4 py-3 text-sm shadow-[var(--shadow-ms-sm)]"
+        style={{
+          backgroundColor: 'var(--color-surface)',
+          borderColor: 'var(--color-border)',
+          color: 'var(--color-text)',
+        }}
+      >
+        <div className="mb-2 flex items-center gap-2 text-[11px]">
+          <span className="font-medium text-[var(--color-text-2)]">Assistant</span>
+          {modelName ? (
+            <span className="rounded-full border border-[var(--color-border)] px-2 py-0.5 text-[var(--color-text-2)]">
+              {modelName}
+            </span>
+          ) : null}
+          <span className="text-[var(--color-muted)]">{text ? 'Responding…' : 'Thinking…'}</span>
+        </div>
         {text ? (
           <div className="whitespace-pre-wrap break-words">{text}</div>
         ) : (
-          <div className="flex items-center gap-2 text-text-muted">
-            <span className="inline-block h-2 w-2 animate-pulse rounded-full bg-blue-500" />
-            <span className="inline-block h-2 w-2 animate-pulse rounded-full bg-blue-500 [animation-delay:0.2s]" />
-            <span className="inline-block h-2 w-2 animate-pulse rounded-full bg-blue-500 [animation-delay:0.4s]" />
+          <div className="flex items-center gap-2 text-[var(--color-muted)]">
+            <span className="inline-block h-2 w-2 animate-pulse rounded-full bg-[var(--color-ms-blue-500)]" />
+            <span className="inline-block h-2 w-2 animate-pulse rounded-full bg-[var(--color-ms-blue-500)] [animation-delay:0.2s]" />
+            <span className="inline-block h-2 w-2 animate-pulse rounded-full bg-[var(--color-ms-blue-500)] [animation-delay:0.4s]" />
           </div>
         )}
-        <div className="mt-1 flex items-center gap-1 text-xs text-text-muted">
-          <span className="inline-block h-1.5 w-1.5 animate-pulse rounded-full bg-blue-500" />
-          {text ? 'Responding...' : 'Thinking...'}
+        {thinking ? (
+          <div
+            className="mt-3 rounded-2xl border px-3 py-2 font-mono text-xs whitespace-pre-wrap"
+            style={{
+              backgroundColor: 'var(--color-bg-deep)',
+              borderColor: 'var(--color-border)',
+              color: 'var(--color-text-2)',
+            }}
+          >
+            {thinking}
+          </div>
+        ) : null}
+        <div className="mt-2 flex items-center gap-2 text-xs text-[var(--color-muted)]">
+          <span className="inline-block h-1.5 w-1.5 animate-pulse rounded-full bg-[var(--color-ms-blue-500)]" />
+          <span>{quip ?? (text ? 'Responding…' : 'Thinking…')}</span>
         </div>
       </div>
     </div>