doc: DEVELOPMENT.md: Permissions errors when installing from source: npm install -g @google/gemini-cli

### Server

gcloud-mcp

### What did you do?

Following the instructions in `development.MD`, I get a permission error when I run `npm install -g @google/gemini-cli`

Is there an alternate way to install?

### What did you see happen?

```
❯ npm install -g @google/gemini-cli
npm warn Unknown builtin config "globalignorefile". This will stop working in the next major version of npm.
npm error code EACCES
npm error syscall mkdir
npm error path /usr/local/lib/node_modules/@google/gemini-cli
npm error errno -13
npm error Error: EACCES: permission denied, mkdir '/usr/local/lib/node_modules/@google/gemini-cli'
npm error at async mkdir (node:internal/fs/promises:858:10)
npm error at async /usr/local/lib/node_modules/npm/node_modules/@npmcli/arborist/lib/arborist/reify.js:639:20
npm error at async Promise.allSettled (index 0)
npm error at async [reifyPackages] (/usr/local/lib/node_modules/npm/node_modules/@npmcli/arborist/lib/arborist/reify.js:337:11)
npm error at async Arborist.reify (/usr/local/lib/node_modules/npm/node_modules/@npmcli/arborist/lib/arborist/reify.js:142:5)
npm error at async Install.exec (/usr/local/lib/node_modules/npm/lib/commands/install.js:149:5)
npm error at async Npm.exec (/usr/local/lib/node_modules/npm/lib/npm.js:208:9)
npm error at async module.exports (/usr/local/lib/node_modules/npm/lib/cli/entry.js:67:5) {
npm error errno: -13,
npm error code: 'EACCES',
npm error syscall: 'mkdir',
npm error path: '/usr/local/lib/node_modules/@google/gemini-cli'
npm error }
npm error
npm error The operation was rejected by your operating system.
npm error It is likely you do not have the permissions to access this file as the current user
npm error
npm error If you believe this might be a permissions issue, please double-check the
npm error permissions of the file and its containing directories, or try running
npm error the command again as root/Administrator.
npm error A complete log of this run can be found in: /usr/local/google/home/[REDACTED]/.npm/_logs/2025-08-27T17_18_20_244Z-debug-0.log
```

### What did you expect to see?

Installation success.

Start with the installation instructions in development.MD and reproduce the reported `npm install -g @google/gemini-cli` command. Update the documented source-install steps with an alternate approach for the EACCES permission error, then verify that the instructions describe a successful installation.

Written by the indexing model from the issue text.