Conflict when installing MCP and Agent Skills: Extension "firebase" is already installed

There is a naming conflict when attempting to install both the Firebase MCP extension and the Agent Skills extension. It appears that both extensions use the same identifier ("firebase") within the Gemini CLI, preventing them from coexisting in the same environment.

## Steps to Reproduce

Install the first extension:

```
gemini extensions install https://github.com/gemini-cli-extensions/firebase/
```

Attempt to install the second extension:

```
gemini extensions install https://github.com/firebase/agent-skills
```

## Actual Behavior

The CLI returns the following error message during the second installation attempt: `Extension "firebase" is already installed. Please uninstall it first.`

## Expected Behavior

Users should be able to install both extensions simultaneously, as they provide different sets of functionalities (one for MCP and another for Agent Skills), even if they both interface with Firebase.

## Environment Data

- Tool: gemini-cli
- Error Message: `Extension "firebase" is already installed. Please uninstall it first.`

## Potential Cause

Both repositories likely define their extension ID as `firebase` in their respective configuration files, causing the CLI to block the second installation to prevent overwriting.