feat: backup/restore, user profile popover, image compress, video blur, wake lock

- backup/restore dialog + user profile popover components
- image compression, video blur, wake lock utilities
- message cache + conversation messages hook refinements
- call context, active speakers, screen share dialog tweaks
- audio + screen share settings persistence
- refreshed app icons (smaller sizes) across all platforms

apps/desktop/src/lib/useConversationMessages.ts

@@ -473,6 +473,35 @@ export function useConversationMessages({ conversationId, userId, deviceId }: Ar
       const priv = privateKeyRef.current;
       if (!priv) throw new Error('private key not loaded');
 
+      // Slash-command: /tempmsg <seconds> <text> sends an ephemeral message
+      // that the sender auto-deletes after the window elapses. Both peers
+      // see the countdown via the expireMs field embedded in the plaintext
+      // payload — no server support required.
+      const tempMatch = /^\/tempmsg\s+(\d+)\s+([\s\S]+)$/i.exec(trimmed);
+      if (tempMatch && images.length === 0) {
+        const seconds = Math.min(3600, Math.max(5, parseInt(tempMatch[1]!, 10)));
+        const body = tempMatch[2]!.trim();
+        const payload = JSON.stringify({
+          v: 1,
+          type: 'text',
+          text: body,
+          attachments: [],
+          expireMs: seconds * 1000,
+        });
+        try {
+          await sendText(conversationId, userId, deviceId, priv, payload, replyToId);
+        } catch (err: unknown) {
+          const msg = err instanceof Error ? err.message : 'send failed';
+          enqueueOutbox({
+            conversationId,
+            text: payload,
+            replyToId,
+            error: msg,
+          });
+        }
+        return;
+      }
+
       // Text-only path is retryable — if the network is down or the server
       // rejects transiently, stash in the outbox and keep the UI optimistic.
       // Attachments can't be deferred (large payloads, uploaded separately),