feat(initial): scaffold @push.rocks/smartchat with core, CLI, and web layers

Three-layer architecture built on @push.rocks/smartagent:
- ts/ — ChatSession wrapping runAgent() with conversation state management
- ts_cli/ — ink-based terminal chat TUI (React.createElement, no JSX)
- ts_web/ — Lit web components (smartchat-window, smartchat-message, smartchat-input)

ts_cli/components.chatapp.ts

@@ -0,0 +1,103 @@
+import { React, h, Box, Text, useInput, useApp, ChatSession } from './plugins.js';
+import type { LanguageModelV3, ToolSet, IChatUsage } from './plugins.js';
+import { MessageList } from './components.messagelist.js';
+import { InputArea } from './components.inputarea.js';
+import { StatusBar } from './components.statusbar.js';
+import type { IChatMessage } from './components.message.js';
+
+export interface IChatAppProps {
+  model: LanguageModelV3;
+  system?: string;
+  tools?: ToolSet;
+  maxSteps?: number;
+  modelName?: string;
+}
+
+const emptyUsage: IChatUsage = { inputTokens: 0, outputTokens: 0, totalTokens: 0, turns: 0 };
+
+export function ChatApp({ model, system, tools, maxSteps, modelName }: IChatAppProps): React.ReactElement {
+  const { exit } = useApp();
+  const [messages, setMessages] = React.useState<IChatMessage[]>([]);
+  const [streamingText, setStreamingText] = React.useState('');
+  const [busy, setBusy] = React.useState(false);
+  const [usage, setUsage] = React.useState<IChatUsage>({ ...emptyUsage });
+
+  const sessionRef = React.useRef<ChatSession | null>(null);
+
+  if (!sessionRef.current) {
+    sessionRef.current = new ChatSession(
+      { model, system, tools, maxSteps: maxSteps ?? 20 },
+      {
+        onToken: (delta) => {
+          setStreamingText((prev) => prev + delta);
+        },
+        onToolCall: (name, input) => {
+          setMessages((prev) => [
+            ...prev,
+            {
+              role: 'tool' as const,
+              content: '',
+              toolName: name,
+              toolInput: typeof input === 'string' ? input : JSON.stringify(input),
+            },
+          ]);
+        },
+      },
+    );
+  }
+
+  useInput((input, key) => {
+    if (input === 'c' && key.ctrl) {
+      exit();
+    }
+    if (input === 'l' && key.ctrl) {
+      setMessages([]);
+      setStreamingText('');
+      sessionRef.current?.clear();
+      setUsage({ ...emptyUsage });
+    }
+  });
+
+  const handleSubmit = async (text: string) => {
+    if (busy) return;
+
+    if (text === '/clear') {
+      setMessages([]);
+      setStreamingText('');
+      sessionRef.current?.clear();
+      setUsage({ ...emptyUsage });
+      return;
+    }
+
+    if (text === '/quit' || text === '/exit') {
+      exit();
+      return;
+    }
+
+    setMessages((prev) => [...prev, { role: 'user', content: text }]);
+    setBusy(true);
+    setStreamingText('');
+
+    try {
+      const result = await sessionRef.current!.send(text);
+      setStreamingText('');
+      setMessages((prev) => [...prev, { role: 'assistant', content: result.text }]);
+      setUsage(sessionRef.current!.getUsage());
+    } catch (error) {
+      const errMsg = error instanceof Error ? error.message : String(error);
+      setMessages((prev) => [...prev, { role: 'assistant', content: `Error: ${errMsg}` }]);
+    } finally {
+      setBusy(false);
+    }
+  };
+
+  return h(Box, { flexDirection: 'column' as const },
+    h(Box, { paddingX: 1 },
+      h(Text, { bold: true, color: 'cyan' }, 'smartchat'),
+      modelName ? h(Text, { dimColor: true }, ` \u2014 ${modelName}`) : null,
+    ),
+    h(MessageList, { messages, streamingText, busy }),
+    h(InputArea, { disabled: busy, onSubmit: handleSubmit }),
+    h(StatusBar, { modelName, usage, busy }),
+  );
+}