feat: add channel browser for discovering and joining channels (#42)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

desktop/src/shared/api/tauri.ts

@@ -73,6 +73,7 @@ type RawChannel = {
   archived_at: string | null;
   participants: string[];
   participant_pubkeys: string[];
+  is_member?: boolean;
 };
 
 type RawChannelDetail = RawChannel & {
@@ -225,6 +226,7 @@ function fromRawChannel(channel: RawChannel): Channel {
     archivedAt: channel.archived_at,
     participants: channel.participants,
     participantPubkeys: channel.participant_pubkeys,
+    isMember: channel.is_member ?? true,
   };
 }
 

desktop/src/shared/api/types.ts

@@ -15,6 +15,7 @@ export type Channel = {
   archivedAt: string | null;
   participants: string[];
   participantPubkeys: string[];
+  isMember: boolean;
 };
 
 export type ChannelDetail = Channel & {