Don't steal focus when an agent spawns a child via MCP

internal/app/app.go

@@ -700,8 +700,26 @@ func (st *uiState) scratchpadsChanged() {
 	}
 }
 
-// OnChildSpawned auto-focuses the new child.
+// OnChildSpawned auto-focuses the new child when the spawn came from
+// the user (palette, persistence restore, or an external MCP client with
+// no resolved identity). When ParentID is set — meaning a patterm-managed
+// agent spawned this child via spawn_agent/spawn_process — focus stays
+// on whatever the user was watching; the new child is still surfaced in
+// the sidebar/tab bar so it's reachable via the palette or select_process.
 func (st *uiState) OnChildSpawned(c *Child) {
+	if c.ParentID != "" {
+		st.mu.Lock()
+		if st.palette != nil {
+			st.palette.children = st.sess.Children()
+			st.palette.focused = st.focusedID
+			st.palette.rebuild()
+			st.renderPaletteLocked()
+		}
+		st.mu.Unlock()
+		st.drawTabBar()
+		st.drawSidebar()
+		return
+	}
 	st.marquee.reset()
 	layout := st.layoutSnapshot()
 	onAlt := childIsOnAlt(c)