feat: add inline citations and thread management features

Citations:
- Add citations parsing utilities for extracting source references from AI responses
- Render inline citations as hover card badges in message content
- Display citation cards with title, URL, and description on hover
- Add citation badge rendering in artifact markdown preview
- Update prompt to guide AI to output citations in correct format

Thread Management:
- Add rename functionality for chat threads with dialog UI
- Add share functionality to copy thread link to clipboard
- Share links use Vercel URL for production accessibility
- Add useRenameThread hook for thread title updates

i18n:
- Add translations for rename, share, cancel, save, and linkCopied

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/core/citations/index.ts

@@ -0,0 +1,8 @@
+export {
+  parseCitations,
+  buildCitationMap,
+  extractDomainFromUrl,
+  isCitationsBlockIncomplete,
+} from "./utils";
+
+export type { Citation, ParseCitationsResult } from "./utils";

frontend/src/core/citations/utils.ts

@@ -0,0 +1,124 @@
+/**
+ * Citation data structure representing a source reference
+ */
+export interface Citation {
+  id: string;
+  title: string;
+  url: string;
+  snippet: string;
+}
+
+/**
+ * Result of parsing citations from content
+ */
+export interface ParseCitationsResult {
+  citations: Citation[];
+  cleanContent: string;
+}
+
+/**
+ * Parse citations block from message content.
+ *
+ * The citations block format:
+ * <citations>
+ * {"id": "cite-1", "title": "Page Title", "url": "https://example.com", "snippet": "Description"}
+ * {"id": "cite-2", "title": "Another Page", "url": "https://example2.com", "snippet": "Description"}
+ * </citations>
+ *
+ * @param content - The raw message content that may contain a citations block
+ * @returns Object containing parsed citations array and content with citations block removed
+ */
+export function parseCitations(content: string): ParseCitationsResult {
+  if (!content) {
+    return { citations: [], cleanContent: content };
+  }
+
+  // Match the citations block at the start of content (with possible leading whitespace)
+  const citationsRegex = /^\s*<citations>([\s\S]*?)<\/citations>/;
+  const match = citationsRegex.exec(content);
+
+  if (!match) {
+    return { citations: [], cleanContent: content };
+  }
+
+  const citationsBlock = match[1] ?? "";
+  const citations: Citation[] = [];
+
+  // Parse each line as JSON
+  const lines = citationsBlock.split("\n");
+  for (const line of lines) {
+    const trimmed = line.trim();
+    if (trimmed?.startsWith("{")) {
+      try {
+        const citation = JSON.parse(trimmed) as Citation;
+        // Validate required fields
+        if (citation.id && citation.url) {
+          citations.push({
+            id: citation.id,
+            title: citation.title || "",
+            url: citation.url,
+            snippet: citation.snippet || "",
+          });
+        }
+      } catch {
+        // Skip invalid JSON lines - this can happen during streaming
+      }
+    }
+  }
+
+  // Remove the citations block from content
+  const cleanContent = content.replace(citationsRegex, "").trim();
+
+  return { citations, cleanContent };
+}
+
+/**
+ * Build a map from URL to Citation for quick lookup
+ *
+ * @param citations - Array of citations
+ * @returns Map with URL as key and Citation as value
+ */
+export function buildCitationMap(
+  citations: Citation[],
+): Map<string, Citation> {
+  const map = new Map<string, Citation>();
+  for (const citation of citations) {
+    map.set(citation.url, citation);
+  }
+  return map;
+}
+
+/**
+ * Extract the domain name from a URL for display
+ *
+ * @param url - Full URL string
+ * @returns Domain name or the original URL if parsing fails
+ */
+export function extractDomainFromUrl(url: string): string {
+  try {
+    const urlObj = new URL(url);
+    // Remove 'www.' prefix if present
+    return urlObj.hostname.replace(/^www\./, "");
+  } catch {
+    return url;
+  }
+}
+
+/**
+ * Check if content is still receiving the citations block (streaming)
+ * This helps determine if we should wait before parsing
+ *
+ * @param content - The current content being streamed
+ * @returns true if citations block appears to be incomplete
+ */
+export function isCitationsBlockIncomplete(content: string): boolean {
+  if (!content) {
+    return false;
+  }
+
+  // Check if we have an opening tag but no closing tag
+  const hasOpenTag = content.includes("<citations>");
+  const hasCloseTag = content.includes("</citations>");
+
+  return hasOpenTag && !hasCloseTag;
+}

frontend/src/core/i18n/locales/en-US.ts

@@ -11,6 +11,8 @@ export const enUS: Translations = {
     home: "Home",
     settings: "Settings",
     delete: "Delete",
+    rename: "Rename",
+    share: "Share",
     openInNewWindow: "Open in new window",
     close: "Close",
     more: "More",
@@ -24,6 +26,8 @@ export const enUS: Translations = {
     loading: "Loading...",
     code: "Code",
     preview: "Preview",
+    cancel: "Cancel",
+    save: "Save",
   },
 
   // Welcome
@@ -38,6 +42,7 @@ export const enUS: Translations = {
     copyToClipboard: "Copy to clipboard",
     copiedToClipboard: "Copied to clipboard",
     failedToCopyToClipboard: "Failed to copy to clipboard",
+    linkCopied: "Link copied to clipboard",
   },
 
   // Input Box

frontend/src/core/i18n/locales/types.ts

@@ -9,6 +9,8 @@ export interface Translations {
     home: string;
     settings: string;
     delete: string;
+    rename: string;
+    share: string;
     openInNewWindow: string;
     close: string;
     more: string;
@@ -22,6 +24,8 @@ export interface Translations {
     loading: string;
     code: string;
     preview: string;
+    cancel: string;
+    save: string;
   };
 
   // Welcome
@@ -35,6 +39,7 @@ export interface Translations {
     copyToClipboard: string;
     copiedToClipboard: string;
     failedToCopyToClipboard: string;
+    linkCopied: string;
   };
 
   // Input Box

frontend/src/core/i18n/locales/zh-CN.ts

@@ -11,6 +11,8 @@ export const zhCN: Translations = {
     home: "首页",
     settings: "设置",
     delete: "删除",
+    rename: "重命名",
+    share: "分享",
     openInNewWindow: "在新窗口打开",
     close: "关闭",
     more: "更多",
@@ -24,6 +26,8 @@ export const zhCN: Translations = {
     loading: "加载中...",
     code: "代码",
     preview: "预览",
+    cancel: "取消",
+    save: "保存",
   },
 
   // Welcome
@@ -38,6 +42,7 @@ export const zhCN: Translations = {
     copyToClipboard: "复制到剪贴板",
     copiedToClipboard: "已复制到剪贴板",
     failedToCopyToClipboard: "复制到剪贴板失败",
+    linkCopied: "链接已复制到剪贴板",
   },
 
   // Input Box

frontend/src/core/threads/hooks.ts

@@ -186,3 +186,43 @@ export function useDeleteThread() {
     },
   });
 }
+
+export function useRenameThread() {
+  const queryClient = useQueryClient();
+  const apiClient = getAPIClient();
+  return useMutation({
+    mutationFn: async ({
+      threadId,
+      title,
+    }: {
+      threadId: string;
+      title: string;
+    }) => {
+      await apiClient.threads.update(threadId, {
+        metadata: { title },
+      });
+    },
+    onSuccess(_, { threadId, title }) {
+      queryClient.setQueriesData(
+        {
+          queryKey: ["threads", "search"],
+          exact: false,
+        },
+        (oldData: Array<AgentThread>) => {
+          return oldData.map((t) => {
+            if (t.thread_id === threadId) {
+              return {
+                ...t,
+                metadata: {
+                  ...t.metadata,
+                  title,
+                },
+              };
+            }
+            return t;
+          });
+        },
+      );
+    },
+  });
+}