feat: 品牌裁剪弹窗/Markdown 行内短代码与详情视频块等

新增：
- BrandCropModal 品牌图裁剪弹窗 + cropImage 工具
- Markdown 行内短代码（inlineShortcodes + remark 插件）
- MdDetails 折叠块、MdVideo 视频块组件
- directiveBlocks/inlineShortcodes 测试

其它：
- 聊天后端（handler/service chat）调整
- Markdown 渲染链路、编辑器、全局样式与品牌相关面板更新

frontend/lib/directiveBlocks.ts

@@ -25,7 +25,9 @@ export type ContentSegment =
       body: string;
     }
   | { type: "timeline"; items: TimelineItem[]; rawBody: string }
-  | { type: "entries"; items: EntryItem[]; rawBody: string };
+  | { type: "entries"; items: EntryItem[]; rawBody: string }
+  | { type: "details"; title: string; body: string }
+  | { type: "video"; provider: "bilibili" | "youtube"; id: string };
 
 function isTimelineClose(line: string): boolean {
   return line.trim().toLowerCase() === "[/timeline]";
@@ -35,6 +37,68 @@ function isTimelineOpen(trimmed: string): boolean {
   return trimmed.toLowerCase() === "[timeline]";
 }
 
+/* ---------- [details] 折叠面板 ---------- */
+
+const DETAILS_OPEN_RE = /^\[details(?:\s+([^\]]*))?\]$/i;
+export const DETAILS_DEFAULT_TITLE = "点击展开";
+
+function isDetailsClose(line: string): boolean {
+  return line.trim().toLowerCase() === "[/details]";
+}
+
+/** 开标记整行匹配：[details 标题文字]；标题缺省「点击展开」 */
+export function isDetailsOpen(trimmed: string): boolean {
+  return DETAILS_OPEN_RE.test(trimmed);
+}
+
+export function parseDetailsOpen(trimmed: string): string {
+  const m = trimmed.match(DETAILS_OPEN_RE);
+  const title = (m?.[1] ?? "").trim();
+  return title || DETAILS_DEFAULT_TITLE;
+}
+
+/* ---------- [bilibili] / [youtube] 视频嵌入（整行单标记） ---------- */
+
+const VIDEO_LINE_RE = /^\[(bilibili|youtube)\]([^\[\]]+)\[\/\1\]$/i;
+const BILI_BV_RE = /^BV[0-9A-Za-z]{8,12}$/;
+const BILI_URL_BV_RE = /\/video\/(BV[0-9A-Za-z]{8,12})/;
+const YT_ID_RE = /^[0-9A-Za-z_-]{6,20}$/;
+
+/**
+ * 裸输入解析：BV 号 / B站视频链接 / YouTube ID / youtu.be、watch?v= 链接。
+ * 短代码行与编辑器「插入视频」表单共用；解析失败返回 null。
+ */
+export function parseVideoInput(
+  raw: string
+): { provider: "bilibili" | "youtube"; id: string } | null {
+  const s = raw.trim();
+  if (!s || /[\s<>"']/.test(s)) return null;
+  const bvFromUrl = s.match(BILI_URL_BV_RE);
+  if (bvFromUrl) return { provider: "bilibili", id: bvFromUrl[1] };
+  if (BILI_BV_RE.test(s)) return { provider: "bilibili", id: s };
+  if (/youtu\.?be/i.test(s)) {
+    const m = s.match(/(?:youtu\.be\/|[?&]v=)([0-9A-Za-z_-]{6,20})/);
+    return m ? { provider: "youtube", id: m[1] } : null;
+  }
+  if (YT_ID_RE.test(s)) return { provider: "youtube", id: s };
+  return null;
+}
+
+/**
+ * 整行 `[bilibili]…[/bilibili]` / `[youtube]…[/youtube]`。
+ * 标签名与内容平台不一致、或内容解析失败时返回 null（该行按普通 Markdown 处理）。
+ */
+export function parseVideoLine(
+  trimmed: string
+): { provider: "bilibili" | "youtube"; id: string } | null {
+  const m = trimmed.match(VIDEO_LINE_RE);
+  if (!m) return null;
+  const provider = m[1].toLowerCase() as "bilibili" | "youtube";
+  const parsed = parseVideoInput(m[2]);
+  if (!parsed || parsed.provider !== provider) return null;
+  return parsed;
+}
+
 /**
  * 先拆时间线，再对普通 md/hide 段做 hide 拆分。
  * 时间线与 hide 互不嵌套；解析失败时整段当普通 Markdown。
@@ -53,7 +117,11 @@ export function splitContentSegments(
   }
   const lines = content.replace(/\r\n/g, "\n").replace(/\r/g, "\n").split("\n");
   const raw: Array<
-    { type: "md"; text: string } | { type: "timeline"; body: string } | { type: "entries"; body: string }
+    | { type: "md"; text: string }
+    | { type: "timeline"; body: string }
+    | { type: "entries"; body: string }
+    | { type: "details"; title: string; body: string }
+    | { type: "video"; provider: "bilibili" | "youtube"; id: string }
   > = [];
   let buf: string[] = [];
   let inCode = false;
@@ -137,6 +205,29 @@ export function splitContentSegments(
       continue;
     }
 
+    // [details 标题]…[/details] 折叠面板：嵌套开标签视为失败按 md 处理
+    if (isDetailsOpen(trimmed)) {
+      const hit = scanBlock(isDetailsOpen, isDetailsClose);
+      if (!hit) {
+        buf.push(lines[i]);
+        i++;
+        continue;
+      }
+      flushMd();
+      raw.push({ type: "details", title: parseDetailsOpen(trimmed), body: hit.body });
+      i = hit.end + 1;
+      continue;
+    }
+
+    // [bilibili]…[/bilibili] / [youtube]…[/youtube] 整行视频嵌入
+    const video = parseVideoLine(trimmed);
+    if (video) {
+      flushMd();
+      raw.push({ type: "video", ...video });
+      i++;
+      continue;
+    }
+
     // [entries:off] 例外块：body 原样进 md 缓冲（标记行丢弃），
     // 不再参与 entries/timeline 拆分；未闭合时整块当普通 Markdown
     if (isEntriesOffOpen(trimmed)) {
@@ -174,6 +265,14 @@ export function splitContentSegments(
       });
       continue;
     }
+    if (part.type === "details") {
+      out.push({ type: "details", title: part.title, body: part.body });
+      continue;
+    }
+    if (part.type === "video") {
+      out.push({ type: "video", provider: part.provider, id: part.id });
+      continue;
+    }
     const hideSegs = splitHideSegments(part.text) as HideSegment[];
     for (const s of hideSegs) {
       if (s.type === "md") {