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_web/smartchat-message.ts

@@ -0,0 +1,78 @@
+import { LitElement, html, css } from './plugins.js';
+import type { CSSResult, TemplateResult } from './plugins.js';
+
+export class SmartchatMessage extends LitElement {
+  declare role: 'user' | 'assistant' | 'tool';
+  declare content: string;
+  declare toolName: string;
+
+  static properties = {
+    role: { type: String },
+    content: { type: String },
+    toolName: { type: String },
+  };
+
+  static styles: CSSResult = css`
+    :host {
+      display: block;
+      margin-bottom: 8px;
+    }
+
+    .message {
+      padding: 8px 12px;
+      border-radius: 8px;
+      max-width: 85%;
+      word-wrap: break-word;
+      white-space: pre-wrap;
+    }
+
+    .user {
+      background: var(--smartchat-user-bubble, #2563eb);
+      color: var(--smartchat-user-text, #fff);
+      margin-left: auto;
+      border-bottom-right-radius: 2px;
+    }
+
+    .assistant {
+      background: var(--smartchat-assistant-bubble, #374151);
+      color: var(--smartchat-assistant-text, #e5e7eb);
+      margin-right: auto;
+      border-bottom-left-radius: 2px;
+    }
+
+    .tool {
+      background: var(--smartchat-tool-bubble, #1e293b);
+      color: var(--smartchat-tool-text, #94a3b8);
+      margin-right: auto;
+      font-size: 0.85em;
+      font-family: monospace;
+      border-left: 3px solid var(--smartchat-tool-accent, #6366f1);
+    }
+
+    .tool-name {
+      font-weight: bold;
+      margin-bottom: 4px;
+      color: var(--smartchat-tool-accent, #6366f1);
+    }
+  `;
+
+  constructor() {
+    super();
+    this.role = 'user';
+    this.content = '';
+    this.toolName = '';
+  }
+
+  render(): TemplateResult {
+    return html`
+      <div class="message ${this.role}">
+        ${this.role === 'tool' && this.toolName
+          ? html`<div class="tool-name">${this.toolName}</div>`
+          : ''}
+        <div>${this.content}</div>
+      </div>
+    `;
+  }
+}
+
+customElements.define('smartchat-message', SmartchatMessage);