feat(message): implement message search functionality

Add ability to search messages within a specific conversation. This includes:
- New `MessageSearchScreen` for displaying search results.
- `MessageRepository.searchByConversation` to query messages by keyword and conversation ID.
- Integration of search entry points in `GroupInfoScreen` and `PrivateChatInfoScreen`.
- Support for scrolling to a specific message sequence (`scrollToSeq`) when navigating from search results.
- Enhanced `HighlightText` component to support custom highlight styles.

feat(message): implement message search functionality

src/navigation/hrefs.ts

@@ -87,14 +87,16 @@ export function hrefChat(params: {
   groupId?: string;
   groupName?: string;
   groupAvatar?: string;
+  scrollToSeq?: number;
 }): string {
-  const { conversationId, userId, isGroupChat, groupId, groupName, groupAvatar } = params;
+  const { conversationId, userId, isGroupChat, groupId, groupName, groupAvatar, scrollToSeq } = params;
   const q = new URLSearchParams();
   if (userId) q.set('userId', userId);
   if (isGroupChat) q.set('isGroupChat', '1');
   if (groupId != null && groupId !== '') q.set('groupId', String(groupId));
   if (groupName) q.set('groupName', groupName);
   if (groupAvatar) q.set('groupAvatar', groupAvatar);
+  if (scrollToSeq != null) q.set('scrollToSeq', String(scrollToSeq));
   const qs = q.toString();
   return `/chat/${encodeURIComponent(conversationId)}${qs ? `?${qs}` : ''}`;
 }
@@ -131,6 +133,19 @@ export function hrefGroupInviteDetail(message: SystemMessageResponse): string {
   return `/group/invite?messageId=${encodeURIComponent(message.id)}`;
 }
 
+export function hrefMessageSearch(params: {
+  conversationId: string;
+  conversationName?: string;
+  isGroupChat?: boolean;
+}): string {
+  const q = new URLSearchParams({
+    conversationId: params.conversationId,
+  });
+  if (params.conversationName) q.set('conversationName', params.conversationName);
+  if (params.isGroupChat) q.set('isGroupChat', '1');
+  return `/chat/message-search?${q.toString()}`;
+}
+
 export function hrefPrivateChatInfo(params: {
   conversationId: string;
   userId: string;