[Bug]: PHP 8.3 php.ini missing auto_prepend_file and herd-ext extension lines (dump() undefined)

### Platform
macOS

### Operating system version
macOS 26.4.1

### System architecture
Apple Silicon (M4 Pro)

### Herd Version
1.28.0

### PHP Version
8.3 (FPM, served via herd.sock)

### Bug description
On a Herd Pro install with PHP 8.3 enabled, calling `dump()` from PHP code produces:

> Fatal error: Uncaught Error: Call to undefined function dump()

The cause: \`~/Library/Application Support/Herd/config/php/83/php.ini\` is missing the two lines that wire up the dump helper. The same file for 8.2, 8.4, and 8.5 contains them.

Working (\`84/php.ini\`):

\`\`\`
auto_prepend_file=/Applications/Herd.app/Contents/Resources/valet/dump-loader.php
extension=/Applications/Herd.app/Contents/Resources/herd-ext/herd-84-arm64.so
\`\`\`

Broken (\`83/php.ini\`):

\`\`\`
(neither line present)
\`\`\`

The corresponding binary \`/Applications/Herd.app/Contents/Resources/herd-ext/herd-83-arm64.so\` does exist in the app bundle, so it looks like the ini was just never written/regenerated for 8.3.

### Steps to reproduce
1. Install Herd Pro, enable PHP 8.3.
2. Configure a site to use PHP 8.3, with dump interception on.
3. Call \`dump('hello')\` anywhere in the application.
4. Observe a fatal error instead of the value being captured by the Dumps window.

### Workaround
Append the two lines to \`~/Library/Application Support/Herd/config/php/83/php.ini\` (pointing at \`herd-83-arm64.so\`) and run \`herd restart\`.