feat(ui-flow): handle settings-save and settings-discard IPC (Phase 768)

Push state and emit settings-saved/settings-discarded events so composer focus
restores consistently after explicit settings save or discard.

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

index.js

@@ -3152,7 +3152,13 @@ async function dispatchUiMessage (platform, msg, hooks = {}) {
     }
     return true
   }
-  if (t === 'settings-open' || t === 'settings-close' || t === 'settings-section-change') {
+  if (
+    t === 'settings-open' ||
+    t === 'settings-close' ||
+    t === 'settings-section-change' ||
+    t === 'settings-save' ||
+    t === 'settings-discard'
+  ) {
     pushState()
     if (platform.activeChannelId) {
       send({
@@ -3167,6 +3173,12 @@ async function dispatchUiMessage (platform, msg, hooks = {}) {
         scope: msg.scope || 'user',
         guildId: msg.guildId || null
       })
+    } else if (t === 'settings-save' || t === 'settings-discard') {
+      send({
+        type: t === 'settings-save' ? 'settings-saved' : 'settings-discarded',
+        scope: msg.scope || 'user',
+        guildId: msg.guildId || null
+      })
     } else {
       send({
         type: t === 'settings-open' ? 'settings-opened' : 'settings-closed',