Phase 666: IPC for embed retry and composer IME composing state.

Wire retry-link-embed and composer-ime-composing to platform handlers.

Co-authored-by: Cursor <[email protected]>

index.js

@@ -2410,6 +2410,15 @@ async function dispatchUiMessage (platform, msg, hooks = {}) {
     }
     return true
   }
+  if (t === 'composer-ime-composing') {
+    platform.setComposerImeComposing(!!msg.active)
+    return true
+  }
+  if (t === 'retry-link-embed') {
+    await platform.retryLinkEmbedForMessage(msg.messageId)
+    pushState()
+    return true
+  }
   if (t === 'create-channel-webhook') {
     const out = await platform.createChannelWebhook({
       channelId: msg.channelId,