v4: a moderator's or an admin's @everyone in the chat notifies every user — there was no way to reach everyone at once. The new chat:everyone permission, held by moderators and admins, lets a chat message saying @everyone notify every user but its author and those reading the chat, through notifyEveryone, after notifyMentions, so a user also named is told once, by name; the notification is a user_mentioned with everyone set, which the notifications page and the digest word as "mentioned everyone in the chat". chat_messages.mentions_everyone, sent as ChatMessage.mentionsEveryone, is set from the author's role each time the body is written, so a user's @everyone reaches no one, a moderator's edit of a user's message can't make it reach everyone, and a demoted author's next edit loses it. Only an edit that adds @everyone notifies, so fixing an announcement's typo reaches no one new. The client highlights and chimes by the flag, never by the text; Markdown shows @everyone as a mention only in a flagged message, and never links it to a profile. The chat composer offers @everyone first to those who may say it. No account may be named everyone, in any case: migration 0023 adds the column, flags the moderators' and admins' past @everyone messages, renames a user named everyone to everyone_N and drops an alias everyone. 265 backend tests and 681 frontend tests pass, and deno check, tsc, eslint, doc:lint and i18n:compile --strict are clean; checked in screenshots of the chat at 1280 and 390px, with a moderator's and a user's @everyone and the suggestions open.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/test/pages/Notifications.test.tsx

@@ -134,6 +134,17 @@ const n = {
       contextTitle: "",
     },
   }),
+  mentionEveryone: makeNotification({
+    type: "user_mentioned",
+    data: {
+      mentionerId: "m",
+      mentionerUsername: "mo",
+      contextType: "chat",
+      contextId: "y",
+      contextTitle: "",
+      everyone: true,
+    },
+  }),
   mentionPlaylist: makeNotification({
     type: "user_mentioned",
     data: {
@@ -170,8 +181,9 @@ describe("Notifications", () => {
       "/notifications?chat=x",
       "/@bob/playlists/faves",
     ]);
+    expect(await link(/mentioned everyone in/)).toBe("/notifications?chat=y");
     expect(screen.getByText("a comment")).toBeInTheDocument();
-    expect(screen.getByText("the chat")).toBeInTheDocument();
+    expect(screen.getAllByText("the chat")).toHaveLength(2);
     expect(screen.getByText("Faves")).toBeInTheDocument();
   });