fix(presence): leaving Do Not Disturb restores your status instead of "dnd" (#283)

Lotus encodes DND as status_msg "dnd". After switching back to Auto, the
heartbeat read the server's status, adopted "dnd" as the user's own and
kept re-sending it, so the custom status was lost and other clients kept
showing "dnd"; the Settings status field showed "dnd" too.

pickHeartbeatStatus (unit-tested) never adopts the "dnd" sentinel and
falls back to the device's real status; Profile neither mirrors it into
the local status nor shows it in the field.

Verified on the local Synapse: "🎮 Gaming" → DND (unavailable/dnd) → Auto
→ online/"🎮 Gaming" (before: online/"dnd").

Still open in #283: while in DND other clients show the literal "dnd";
that needs MSC3026 busy presence on the homeserver (matrix#19).

Refs #283

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/features/settings/account/Profile.tsx

@@ -57,7 +57,7 @@ import { createUploadAtom, UploadSuccess } from '../../../state/upload';
 import { CompactUploadCardRenderer } from '../../../components/upload-card';
 import { useCapabilities } from '../../../hooks/useCapabilities';
 import { Presence, useUserPresence } from '../../../hooks/useUserPresence';
-import { noteLocalStatusWrite } from '../../../utils/ownStatusSync';
+import { DND_STATUS_SENTINEL, noteLocalStatusWrite } from '../../../utils/ownStatusSync';
 import { ProfileDecoration } from './ProfileDecoration';
 import { EmojiBoard } from '../../../components/emoji-board';
 import { useStatusPresets } from '../../../hooks/useStatusPresets';
@@ -396,7 +396,8 @@ function ProfileStatus() {
   const [presenceStatus] = useSetting(settingsAtom, 'presenceStatus');
   const [hidePresence] = useSetting(settingsAtom, 'hidePresence');
 
-  const initialStatus = presence?.status ?? localStorage.getItem(STATUS_MSG_KEY(userId)) ?? '';
+  const serverStatus = presence?.status === DND_STATUS_SENTINEL ? undefined : presence?.status;
+  const initialStatus = serverStatus ?? localStorage.getItem(STATUS_MSG_KEY(userId)) ?? '';
   const [statusMsg, setStatusMsg] = useState<string>(initialStatus);
   // True while the user has unsaved local edits — prevents a server presence
   // echo from overwriting what the user is currently typing/inserting.
@@ -442,6 +443,9 @@ function ProfileStatus() {
         pendingAppliedRef.current = null; // window elapsed — accept external changes
       }
     }
+    // [Gitea #283] "dnd" is the Do Not Disturb sentinel, not something the user
+    // typed: don't show it in the status field or keep it as their status.
+    if (remoteStatus === DND_STATUS_SENTINEL) return;
     if (remoteStatus) {
       setStatusMsg(remoteStatus);
       localStorage.setItem(STATUS_MSG_KEY(userId), remoteStatus);