feat(home): 首页开场语改成一行问候，占位符改「想聊什么都可以」

开场语从「称呼行 + 追问句」收成 claude.ai 式的单行问候：时段池、
星期池、回访池按顺序拼成一个数组，按 variantSelection 确定性取一条；
名字为空时跳过带称呼的条目。副标题行与 .starter-salutation 下线，
h1 降到 clamp(24px, 2.8vw, 30px) / line-height 1.25。追问改由输入框
占位符承担。

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JUei7K13cYxLHE3Axe4A45

frontend/src/lib/rectification-session-composer-guard.ts

@@ -69,7 +69,7 @@ export function ordinaryComposerPlaceholder(input: {
     return input.presetMessageFinished ? "输入你的称呼" : "Jyotisha 正在输入…";
   }
   if (input.creditsEmpty) return "余额不足，可在账户与点数中补充";
-  return "例如：未来半年是否适合换工作？";
+  return "想聊什么都可以";
 }
 
 export function rectificationOrdinaryComposerReopen(input: {

frontend/src/lib/starter-greeting.ts

@@ -1,72 +1,86 @@
 type GreetingPeriod = "morning" | "noon" | "afternoon" | "evening" | "late-night";
 
-type GreetingVariant = {
-  readonly salutation: (name: string) => string;
-  readonly question: string;
+/**
+ * One line, two to five words, no follow-up question.
+ *
+ * The homepage opening used to be a salutation plus a question ("这么晚还醒着，
+ * {名字}。直接说说最在意的问题吧。") — an office voice that answered for the user
+ * before they had said anything. Asking is the composer placeholder's job now;
+ * the greeting only greets. No metaphors (星 / 月 / 陪), no emoji, no period.
+ */
+const NAME_TOKEN = "{名字}";
+
+const periodGreetings: Record<GreetingPeriod, readonly string[]> = {
+  morning: ["早上好", "早上好，{名字}", "早呀，{名字}"],
+  noon: ["中午好", "中午好，{名字}"],
+  afternoon: ["下午好", "下午好，{名字}"],
+  evening: ["晚上好", "晚上好，{名字}", "今天过得怎么样？"],
+  "late-night": ["夜猫子，晚上好", "还没睡呀，{名字}", "晚安前再聊一会"],
 };
 
-const greetingVariants: Record<GreetingPeriod, readonly GreetingVariant[]> = {
-  morning: [
-    { salutation: (name) => `早上好，${name}。`, question: "今天最想先看什么？" },
-    { salutation: (name) => `${name}，早安。`, question: "今天最该关注哪件事？" },
-    { salutation: (name) => `早上好，${name}。`, question: "想从哪个问题开始？" },
-  ],
-  noon: [
-    { salutation: (name) => `中午好，${name}。`, question: "现在最想理清哪件事？" },
-    { salutation: (name) => `${name}，中午好。`, question: "什么问题最需要方向？" },
-    { salutation: (name) => `午间好，${name}。`, question: "事业、关系或选择，想先聊哪个？" },
-  ],
-  afternoon: [
-    { salutation: (name) => `${name}，下午好。`, question: "现在最想推进哪件事？" },
-    { salutation: (name) => `下午好，${name}。`, question: "今天想先理清什么？" },
-    { salutation: (name) => `${name}，下午好。`, question: "事业、关系或选择，想先聊哪个？" },
-  ],
-  evening: [
-    { salutation: (name) => `晚上好，${name}。`, question: "今天最挂心的是哪件事？" },
-    { salutation: (name) => `${name}，晚上好。`, question: "此刻最想聊哪件事？" },
-    { salutation: (name) => `晚上好，${name}。`, question: "把心里的问题告诉我吧。" },
-  ],
-  "late-night": [
-    { salutation: (name) => `夜深了，${name}。`, question: "此刻最想问什么？" },
-    { salutation: (name) => `${name}，还没休息吗？`, question: "想从哪件事说起？" },
-    { salutation: (name) => `这么晚还醒着，${name}。`, question: "直接说说最在意的问题吧。" },
-  ],
+/** Keyed by `Date#getDay()`. Days with nothing worth saying stay out of the pool. */
+const weekdayGreetings: Readonly<Record<number, readonly string[]>> = {
+  0: ["周日，慢一点"],
+  1: ["周一了，{名字}"],
+  5: ["周五快乐"],
+  6: ["周末愉快，{名字}"],
 };
 
+/** Only reachable once the account has at least one session behind it. */
+const returningGreetings: readonly string[] = [
+  "又见面了，{名字}",
+  "欢迎回来",
+  "嗨，{名字}",
+  "最近还好吗，{名字}？",
+];
+
+function greetingPeriod(hour: number): GreetingPeriod {
+  if (hour >= 5 && hour < 11) return "morning";
+  if (hour >= 11 && hour < 14) return "noon";
+  if (hour >= 14 && hour < 18) return "afternoon";
+  if (hour >= 18 && hour < 23) return "evening";
+  return "late-night";
+}
+
+/**
+ * Every line this moment can produce, in pool order: daypart, weekday, returning.
+ * A blank name drops the lines that would print an empty one; the daypart pool
+ * always keeps a nameless line, so the result is never empty.
+ */
+function starterGreetingPool(name: string, now: Date, hasSessions: boolean): readonly string[] {
+  const templates = [
+    ...periodGreetings[greetingPeriod(now.getHours())],
+    ...(weekdayGreetings[now.getDay()] ?? []),
+    ...(hasSessions ? returningGreetings : []),
+  ];
+  return name ? templates : templates.filter((template) => !template.includes(NAME_TOKEN));
+}
+
 export type StartGreetingParts = {
-  readonly salutation: string;
-  readonly question: string;
+  readonly text: string;
 };
 
 export function createStartGreetingParts(
   name: string,
   now = new Date(),
   variantSelection = Math.random(),
+  hasSessions = false,
 ): StartGreetingParts {
-  const displayName = name.trim() || "你好";
-  const hour = now.getHours();
-  const period: GreetingPeriod = hour >= 5 && hour < 11
-    ? "morning"
-    : hour >= 11 && hour < 14
-      ? "noon"
-      : hour >= 14 && hour < 18
-        ? "afternoon"
-        : hour >= 18 && hour < 23 ? "evening" : "late-night";
-  const variants = greetingVariants[period];
-  const index = Math.min(Math.max(Math.floor(variantSelection * variants.length), 0), variants.length - 1);
-  const variant = variants[index]!;
-  return { salutation: variant.salutation(displayName), question: variant.question };
+  const displayName = name.trim();
+  const pool = starterGreetingPool(displayName, now, hasSessions);
+  const index = Math.min(Math.max(Math.floor(variantSelection * pool.length), 0), pool.length - 1);
+  return { text: pool[index]!.replaceAll(NAME_TOKEN, displayName) };
 }
 
 export function createStartGreeting(
   name: string,
   now = new Date(),
   variantSelection = Math.random(),
+  hasSessions = false,
 ): string {
-  const parts = createStartGreetingParts(name, now, variantSelection);
-  return `${parts.salutation}${parts.question}`;
+  return createStartGreetingParts(name, now, variantSelection, hasSessions).text;
 }
 
 export function createOnboardingFallbackGreeting(name: string): string {
-  return `${name.trim()}，从你此刻最关心的问题开始吧。`;
+  return `欢迎，${name.trim()}`;
 }