docs: Adds uninstall local command for Gemini in all README.md languages.

In Portuguese, my native language, I had to add the entire section of
--local commands.

README.zh-CN.md

@@ -751,6 +751,7 @@ npx get-shit-done-cc --antigravity --global --uninstall
 # 本地安装（当前项目）
 npx get-shit-done-cc --claude --local --uninstall
 npx get-shit-done-cc --opencode --local --uninstall
+npx get-shit-done-cc --gemini --local --uninstall
 npx get-shit-done-cc --codex --local --uninstall
 npx get-shit-done-cc --copilot --local --uninstall
 npx get-shit-done-cc --cursor --local --uninstall