feat: wp lit-mcp divi-check with diff and reference update

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/Integrations/Divi/Release/LineDiff.php

@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Integrations\Divi\Release;
+
+defined('ABSPATH') || exit;
+
+/** A small line diff (longest common subsequence) for wp lit-mcp divi-check --diff. */
+final class LineDiff
+{
+    /**
+     * @param list<string> $old
+     * @param list<string> $new
+     * @return list<string> "  kept", "- removed", "+ added"; "…" between changes more than 2 × $context lines apart.
+     */
+    public static function lines(array $old, array $new, int $context = 2): array
+    {
+        $operations = self::operations($old, $new);
+        $keep = [];
+        foreach ($operations as $i => [$op]) {
+            if ($op === ' ') {
+                continue;
+            }
+            for ($j = max(0, $i - $context); $j <= min(count($operations) - 1, $i + $context); ++$j) {
+                $keep[$j] = true;
+            }
+        }
+
+        $lines = [];
+        $last = null;
+        foreach ($operations as $i => [$op, $line]) {
+            if (! isset($keep[$i])) {
+                continue;
+            }
+            if ($last !== null && $i > $last + 1) {
+                $lines[] = '…';
+            }
+            $lines[] = $op . ' ' . $line;
+            $last = $i;
+        }
+
+        return $lines;
+    }
+
+    /**
+     * @param list<string> $a
+     * @param list<string> $b
+     * @return list<array{0: string, 1: string}>
+     */
+    private static function operations(array $a, array $b): array
+    {
+        $n = count($a);
+        $m = count($b);
+        $lcs = array_fill(0, $n + 1, array_fill(0, $m + 1, 0));
+        for ($i = $n - 1; $i >= 0; --$i) {
+            for ($j = $m - 1; $j >= 0; --$j) {
+                $lcs[$i][$j] = $a[$i] === $b[$j] ? $lcs[$i + 1][$j + 1] + 1 : max($lcs[$i + 1][$j], $lcs[$i][$j + 1]);
+            }
+        }
+
+        $operations = [];
+        $i = 0;
+        $j = 0;
+        while ($i < $n && $j < $m) {
+            if ($a[$i] === $b[$j]) {
+                $operations[] = [' ', $a[$i]];
+                ++$i;
+                ++$j;
+            } elseif ($lcs[$i + 1][$j] >= $lcs[$i][$j + 1]) {
+                $operations[] = ['-', $a[$i++]];
+            } else {
+                $operations[] = ['+', $b[$j++]];
+            }
+        }
+        while ($i < $n) {
+            $operations[] = ['-', $a[$i++]];
+        }
+        while ($j < $m) {
+            $operations[] = ['+', $b[$j++]];
+        }
+
+        return $operations;
+    }
+}