Fix muted rooms showing unread badges (#2581)

fix: detect muted rooms with empty actions array

The mute detection was checking for `actions[0] === "dont_notify"` but
Cinny sets `actions: []` (empty array) when muting a room, which is
the correct behavior per Matrix spec where empty actions means no
notification.

This caused muted rooms to still show unread badges and contribute to
space badge counts.

Fixes the isMutedRule check to handle both:
- Empty actions array (current Matrix spec)
- "dont_notify" string (deprecated but may exist in older rules)

src/app/utils/room.ts

@@ -160,7 +160,8 @@ export const getOrphanParents = (roomToParents: RoomToParents, roomId: string):
 };
 
 export const isMutedRule = (rule: IPushRule) =>
-  rule.actions[0] === 'dont_notify' && rule.conditions?.[0]?.kind === 'event_match';
+  // Check for empty actions (new spec) or dont_notify (deprecated)
+  (rule.actions.length === 0 || rule.actions[0] === 'dont_notify') && rule.conditions?.[0]?.kind === 'event_match';
 
 export const findMutedRule = (overrideRules: IPushRule[], roomId: string) =>
   overrideRules.find((rule) => rule.rule_id === roomId && isMutedRule(rule));