🛡️ Add coverage XML validation

[jordanpartridge]

Problem

Code assumes coverage.xml exists and is valid, leading to cryptic errors when it's not.

Current Risk

File: app/Services/CloverParser.php

• No validation that coverage file exists
• No validation that XML is well-formed
• Silent failures or PHP warnings

Proposed Implementation

if (!file_exists($cloverPath)) {
    throw new \RuntimeException("Coverage file not found: {$cloverPath}");
}

$xml = @simplexml_load_file($cloverPath);
if ($xml === false) {
    throw new \RuntimeException("Invalid coverage XML at: {$cloverPath}");
}

Benefits

• Clear error messages for missing/invalid coverage files
• Prevents XML parsing errors
• Better debugging experience