fix(site): use "Create token" wording in token settings (#27634)

> 🤖 This PR was written by Coder Agents on behalf of Jake Howell.

The token settings page button read **"Add token"**, while everything
else uses **"Create"**:

- The page the button navigates to is titled "Create Token" with a
"Create token" submit button (`CreateTokenPage` / `CreateTokenForm`).
- CLI: `coder tokens create`
- SDK: `CreateToken`
- API: `create-token-api-key` / `CreateTokenRequest`

This aligns the button with the dominant nomenclature by changing "Add
token" → "Create token".

site/src/pages/UserSettingsPage/TokensPage/TokensPage.tsx

@@ -39,7 +39,7 @@ const TokensPage: FC = () => {
 					<Button asChild variant="outline">
 						<RouterLink to="new">
 							<PlusIcon />
-							Add token
+							Create token
 						</RouterLink>
 					</Button>
 				}