fix(chat): fold natal reports and drop homepage topic cards

Homepage no longer waits on /api/onboarding for six starter questions.
Natal answers show the spoken layer first; the Level 2 skeleton sits in a
collapsed 完整分析 block. Wide tables scroll sideways on a phone. Form
inputs are 16px so iOS does not zoom on focus.

frontend/tests/chat-markdown-split.test.ts

@@ -68,7 +68,9 @@ test("the streaming renderer parses the prefix and the tail as two separate docu
   assert.match(contentSource, /const StableMarkdownPrefix = memo\(function StableMarkdownPrefix/);
   assert.match(contentSource, /splitStableMarkdown\(text\)/);
   assert.match(contentSource, /streaming\s*\?\s*<StreamingMarkdown/);
-  // Settled answers still parse once as one document.
-  assert.match(contentSource, /: renderMarkdown\s*\?\s*renderMarkdown\(spoken\)/);
+  // 原值: `: renderMarkdown ? renderMarkdown(spoken)` 只给口语层走 markdown。
+  // 新值: 口语层与报告层都走 `renderProse`。
+  // 原因: 两层可见性后，折叠内外共用同一套解析，避免两套 fallback。
+  assert.match(contentSource, /: renderProse\(spoken, renderMarkdown\)/);
   assert.match(messageRowSource, /streaming=\{message\.state !== "settled"\}/);
 });