Add MSIX workaround note for Register-PwshToClaudeDesktop

MSIX (Microsoft Store) installs virtualize %APPDATA%, causing
Register-PwshToClaudeDesktop to write config to the wrong path.
Added a warning with manual workaround instructions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: yotsuda

README.md

@@ -152,6 +152,11 @@ Register-PwshToClaudeCode
 Register-PwshToClaudeDesktop
 ```
 
+> **⚠️ MSIX (Microsoft Store) installs:** `Register-PwshToClaudeDesktop` may write to the wrong config path due to MSIX filesystem virtualization. If MCP tools don't appear after restart, open Claude Desktop's **Settings → Developer → Edit Config** to find the actual config path, then manually add:
+> ```json
+> { "mcpServers": { "pwsh": { "command": "<paste output of Get-MCPProxyPath -Escape>" } } }
+> ```
+
 **For other MCP clients:** Run `Get-MCPProxyPath -Escape` to get the JSON-escaped executable path, then add it to your client's configuration file manually.
 
 #### 4. Restart your MCP client