Workers silently accepts leading whitespace in secret variable names

### What versions & operating system are you using?

Wrangler 4.118.0
Node.js 24.14.1
npm 11.11.0
Linux Docker container
Windows host with PowerShell 7.6.4

The affected secret was originally created through the "Workers & Pages" dashboard under "Settings" → "Variables and Secrets".

### Please provide a link to a minimal reproduction

N/A

### Describe the Bug

The Workers dashboard accepts secret variable names with accidental leading or trailing spaces.

For example, ` FIREBASE_SERVICE_ACCOUNT_JSON` is deployed as a different binding from `FIREBASE_SERVICE_ACCOUNT_JSON`, without any warning.

This is difficult to notice and causes the expected `env` binding to be `undefined`.

Please trim surrounding whitespace ` ` automatically, or reject the name with a clear validation message before deployment.

### Please provide any relevant error logs

```bash
$ npx wrangler secret list

[
{
"name": " FIREBASE_SERVICE_ACCOUNT_JSON",
"type": "secret_text"
},
{
"name": "OTHER_AUTH_SECRET_WITHOUT_WHITESPACE",
"type": "secret_text"
}
]
```