feat(admin): dock ticket reply composer in conversation and move notes to a dialog

Put the reply composer at the bottom of the conversation card so the
timeline and composer form one viewport-height panel; the send button is
visible on load and Ctrl/Cmd+Enter submits. Internal notes now open in a
dialog instead of expanding inline, so the sidebar no longer grows.

Remove the shared ticket_composer helper and the inline note expansion CSS;
both dialogs share ticket_dialog_head.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/admin/ticket-native-render.test.cjs

@@ -44,7 +44,18 @@ test('workspace loads by ID independent of list filters and keeps the list conte
   assert.match(closed, /aksrt-ticket-detail__closed/);
   assert.match(closed, /data-aksrt-ticket-form="note"/);
   assert.doesNotMatch(closed, /data-aksrt-ticket-form="(?:reply|status)"/);
-  for (const html of [open, closed]) assert.doesNotMatch(html, /<dialog|data-aksrt-dialog-close/);
+  // 回复框是会话卡片的底部，不是独立卡片；工作区唯一的弹窗是内部备注。
+  const conversation = open.match(/<section class="aksrt-ticket-conversation"[^]*?<\/section>/)?.[0] || '';
+  assert.match(conversation, /aksrt-ticket-conversation__scroll[^]*data-aksrt-ticket-form="reply"/);
+  assert.match(conversation, /data-aksrt-ticket-send-shortcut/);
+  assert.match(conversation, /<button type="submit" class="button button-primary">[^]*发送回复<\/button>/);
+  for (const html of [open, closed]) {
+    assert.equal((html.match(/<dialog /g) || []).length, 1);
+    assert.match(html, /<dialog id="aksrt-ticket-note-dialog"[^]*data-aksrt-ticket-form="note"[^]*<\/dialog>/);
+    assert.match(html, /data-aksrt-dialog-open="aksrt-ticket-note-dialog"/);
+  }
+  const sidebar = open.match(/<aside\b[^]*?<\/aside>/)?.[0] || '';
+  assert.doesNotMatch(sidebar, /<textarea|data-aksrt-ticket-form="note"/, 'note input lives only in the dialog');
 });
 
 test('result codes render as one native notice and unknown codes are ignored', () => {