feat: add dynamic canvas placeholder with shared admin config

app/(admin)/settings/admin-settings-client.tsx

@@ -3781,9 +3781,9 @@ export function AdminSettingsClient() {
                 </div>
               </div>
               <div className="grid gap-4 rounded-lg border border-dashed p-4">
-                <div className="text-sm font-medium">新版首页文案配置</div>
+                <div className="text-sm font-medium">首页 / 无限画布对话框文案配置</div>
                 <div className="space-y-2">
-                  <Label htmlFor="lovartComposerPrefix">对话框固定前缀文案</Label>
+                  <Label htmlFor="lovartComposerPrefix">对话框固定前缀文案（首页与无限画布共用）</Label>
                   <Input
                     id="lovartComposerPrefix"
                     value={siteSettings.lovartComposerPrefix}
@@ -3801,7 +3801,7 @@ export function AdminSettingsClient() {
                 </div>
                 <div className="space-y-2">
                   <Label htmlFor="lovartComposerPreviewTexts">
-                    对话框预览文案（每行一条，按顺序轮播打字显示）
+                    对话框预览文案（首页与无限画布共用，每行一条，按顺序轮播打字显示）
                   </Label>
                   <Textarea
                     id="lovartComposerPreviewTexts"

components/canvas/CanvasChatPanel.tsx

@@ -89,6 +89,32 @@ interface CanvasChatPanelProps {
 
 // 建议卡片数据 - 已移除
 const SUGGESTIONS: { title: string; desc: string; image: string }[] = [];
+const CANVAS_COMPOSER_PREFIX_DEFAULT = "让Buyi-ai";
+const CANVAS_COMPOSER_PREVIEW_TEXTS_DEFAULT = [
+  "打造引人注目的社交媒体视觉",
+  "帮我把这张产品图做成高级电商海报",
+  "基于参考图延展 3 套同风格方案",
+];
+
+function normalizeComposerPreviewTail(text: string, fixedPrefix: string) {
+  const trimmed = text.trim();
+  if (!trimmed) return "";
+
+  const sanitizedPrefix = fixedPrefix.trim();
+  if (sanitizedPrefix && trimmed.startsWith(sanitizedPrefix)) {
+    return trimmed.slice(sanitizedPrefix.length).trimStart();
+  }
+
+  const legacyPrefixRemoved = trimmed
+    .replace(/^让\s*buyi[-_ ]?ai\s*/i, "")
+    .replace(/^让\s*lovart\s*/i, "")
+    .trimStart();
+  if (legacyPrefixRemoved !== trimmed) {
+    return legacyPrefixRemoved;
+  }
+
+  return trimmed;
+}
 
 // 获取图片尺寸（保留原图分辨率 + 画布显示尺寸）
 function getImageDimensions(url: string): Promise<{
@@ -2248,6 +2274,8 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
     bannerEnabled?: boolean;
     bannerText?: string;
     bannerLink?: string | null;
+    lovartComposerPrefix?: string | null;
+    lovartComposerPreviewTexts?: string[];
     canvasEnabled?: boolean;
     aiDetailGenerationEnabled?: boolean;
     canvasDefaultModelId?: string | null;
@@ -2292,6 +2320,8 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
     }
     return "";
   }, [session?.user?.email, session?.user?.name]);
+  const [canvasTypedPreviewText, setCanvasTypedPreviewText] = useState("");
+  const [canvasPreviewCursorVisible, setCanvasPreviewCursorVisible] = useState(true);
   const [greetingPeriodText, setGreetingPeriodText] = useState("中午好！");
   useEffect(() => {
     const hour = new Date().getHours();
@@ -2309,6 +2339,95 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
     }
     setGreetingPeriodText("深夜好！");
   }, []);
+  const canvasComposerPrefix = useMemo(
+    () =>
+      String(siteSettings?.lovartComposerPrefix || "").trim() ||
+      CANVAS_COMPOSER_PREFIX_DEFAULT,
+    [siteSettings?.lovartComposerPrefix]
+  );
+  const canvasComposerPreviewTexts = useMemo(() => {
+    const configured = (siteSettings?.lovartComposerPreviewTexts || [])
+      .map((item) => String(item || "").trim())
+      .filter(Boolean);
+    return configured.length > 0
+      ? configured
+      : CANVAS_COMPOSER_PREVIEW_TEXTS_DEFAULT;
+  }, [siteSettings?.lovartComposerPreviewTexts]);
+  const canvasComposerPreviewTails = useMemo(
+    () =>
+      canvasComposerPreviewTexts
+        .map((text) => normalizeComposerPreviewTail(text, canvasComposerPrefix))
+        .filter(Boolean),
+    [canvasComposerPrefix, canvasComposerPreviewTexts]
+  );
+  useEffect(() => {
+    let disposed = false;
+    let timer: ReturnType<typeof setTimeout> | null = null;
+
+    if (canvasComposerPreviewTails.length === 0) {
+      setCanvasTypedPreviewText("");
+      return () => {
+        if (timer) clearTimeout(timer);
+      };
+    }
+
+    let textIndex = 0;
+    let charIndex = 0;
+
+    const typeForward = () => {
+      if (disposed) return;
+      const currentText = canvasComposerPreviewTails[textIndex] || "";
+
+      if (charIndex < currentText.length) {
+        charIndex += 1;
+        setCanvasTypedPreviewText(currentText.slice(0, charIndex));
+        timer = setTimeout(typeForward, 55);
+        return;
+      }
+
+      if (canvasComposerPreviewTails.length === 1) {
+        setCanvasTypedPreviewText(currentText);
+        return;
+      }
+
+      timer = setTimeout(typeBackward, 1200);
+    };
+
+    const typeBackward = () => {
+      if (disposed) return;
+      const currentText = canvasComposerPreviewTails[textIndex] || "";
+
+      if (charIndex > 0) {
+        charIndex -= 1;
+        setCanvasTypedPreviewText(currentText.slice(0, charIndex));
+        timer = setTimeout(typeBackward, 35);
+        return;
+      }
+
+      textIndex = (textIndex + 1) % canvasComposerPreviewTails.length;
+      timer = setTimeout(typeForward, 260);
+    };
+
+    setCanvasTypedPreviewText("");
+    timer = setTimeout(typeForward, 260);
+
+    return () => {
+      disposed = true;
+      if (timer) clearTimeout(timer);
+    };
+  }, [canvasComposerPreviewTails]);
+
+  useEffect(() => {
+    const blinkTimer = setInterval(() => {
+      setCanvasPreviewCursorVisible((value) => !value);
+    }, 450);
+
+    return () => clearInterval(blinkTimer);
+  }, []);
+
+  const canvasDynamicPlaceholder = `${canvasComposerPrefix}${canvasTypedPreviewText}${
+    canvasPreviewCursorVisible ? " |" : ""
+  }`;
   const totalGeneratedImages = Number(userImageStats?.totalImages ?? NaN);
   const aiDetailGenerationEnabled = siteSettings?.aiDetailGenerationEnabled === true;
   const shouldShowCanvasBanner =
@@ -6008,7 +6127,7 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
     : selectedSkillTag?.placeholder?.trim() ||
       (selectedSkillTag
         ? `请输入「${selectedSkillTag.name}」相关需求`
-        : "请输入你的设计需求，例如：绿色椅子 替换 Image");
+        : canvasDynamicPlaceholder || "请输入你的设计需求，例如：绿色椅子 替换 Image");
   const detailProductCount = DETAIL_PRODUCT_SLOT_INDEXES.filter((index) => Boolean(detailSlots[index]?.url)).length;
   const detailModelReady = DETAIL_MODEL_SLOT_INDEX >= 0 ? Boolean(detailSlots[DETAIL_MODEL_SLOT_INDEX]?.url) : false;
   const detailBundleCount = DETAIL_BUNDLE_SLOT_INDEXES.filter((index) => Boolean(detailSlots[index]?.url)).length;