fix(cli): switch default back to terminalBuffer=false and fix regressions introduced for that mode (#24873)

packages/cli/src/ui/__snapshots__/App.test.tsx.snap

@@ -55,6 +55,12 @@ Footer
  Gemini CLI v1.2.3
 
 
+
+Tips for getting started:
+1. Create GEMINI.md files to customize your interactions
+2. /help for more information
+3. Ask coding questions, edit code or run commands
+4. Be specific for the best results
 Composer
 "
 `;