feat: add saved messages, public chat discovery/join, and chat delete options

- add Saved Messages system chat with dedicated API

- add public group/channel metadata and discover/join endpoints

- add chat delete flow with for_all option and channel-wide delete

- switch message actions to context menu and improve reply/forward visuals

- improve microphone permission handling for voice recording

web/src/api/chats.ts

@@ -1,5 +1,5 @@
 import { http } from "./http";
-import type { Chat, ChatType, Message, MessageType } from "../chat/types";
+import type { Chat, ChatType, DiscoverChat, Message, MessageType } from "../chat/types";
 import axios from "axios";
 
 export async function getChats(query?: string): Promise<Chat[]> {
@@ -17,11 +17,24 @@ export async function createChat(type: ChatType, title: string | null, memberIds
   const { data } = await http.post<Chat>("/chats", {
     type,
     title,
+    is_public: false,
     member_ids: memberIds
   });
   return data;
 }
 
+export async function createPublicChat(type: "group" | "channel", title: string, handle: string, description?: string): Promise<Chat> {
+  const { data } = await http.post<Chat>("/chats", {
+    type,
+    title,
+    handle,
+    description,
+    is_public: true,
+    member_ids: []
+  });
+  return data;
+}
+
 export async function getMessages(chatId: number, beforeId?: number): Promise<Message[]> {
   const { data } = await http.get<Message[]>(`/messages/${chatId}`, {
     params: {
@@ -132,3 +145,24 @@ export async function pinMessage(chatId: number, messageId: number | null): Prom
   });
   return data;
 }
+
+export async function deleteChat(chatId: number, forAll: boolean): Promise<void> {
+  await http.delete(`/chats/${chatId}`, { params: { for_all: forAll } });
+}
+
+export async function discoverChats(query?: string): Promise<DiscoverChat[]> {
+  const { data } = await http.get<DiscoverChat[]>("/chats/discover", {
+    params: query?.trim() ? { query: query.trim() } : undefined
+  });
+  return data;
+}
+
+export async function joinChat(chatId: number): Promise<Chat> {
+  const { data } = await http.post<Chat>(`/chats/${chatId}/join`);
+  return data;
+}
+
+export async function getSavedMessagesChat(): Promise<Chat> {
+  const { data } = await http.get<Chat>("/chats/saved");
+  return data;
+}