wiki: add manual update guide for Gemini CLI

05-troubleshooting/gemini-cli-manual-update.md

@@ -0,0 +1,47 @@
+# 🛠️ Gemini CLI: Manual Update Guide
+
+If the automatic update fails or you need to force a specific version of the Gemini CLI, use these steps.
+
+## 🔴 Symptom: Automatic Update Failed
+You may see an error message like:
+`✕ Automatic update failed. Please try updating manually`
+
+## 🟢 Manual Update Procedure
+
+### 1. Verify Current Version
+Check the version currently installed on your system:
+```bash
+gemini --version
+```
+
+### 2. Check Latest Version
+Query the npm registry for the latest available version:
+```bash
+npm show @google/gemini-cli version
+```
+
+### 3. Perform Manual Update
+Use `npm` with `sudo` to update the global package:
+```bash
+sudo npm install -g @google/gemini-cli@latest
+```
+
+### 4. Confirm Update
+Verify that the new version is active:
+```bash
+gemini --version
+```
+
+## 🛠️ Troubleshooting Update Failures
+
+### Permissions Issues
+If you encounter `EACCES` errors without `sudo`, ensure your user has permissions or use `sudo` as shown above.
+
+### Registry Connectivity
+If `npm` cannot reach the registry, check your internet connection or any local firewall/proxy settings.
+
+### Cache Issues
+If the version doesn't update, try clearing the npm cache:
+```bash
+npm cache clean --force
+```