refactor(lint): rewrite structural linters from Ruby to PHP

Fold scripts/lint and scripts/linters/*.rb into a standalone Composer
project under scripts/linters/, matching the scripts/plugin-class-classifier/
convention. Uses no external packages, only PHP + Composer autoloading.

Verified byte-for-byte identical output against the original Ruby
implementation, both on the current repo (all linters pass) and on a
synthetic fixture exercising every violation type.

Entry point moves from `scripts/lint` to `scripts/linters/lint`.

1 files changed, 68 insertions, 0 deletions

diff --git a/scripts/linters/src/Support/FileFinder.php b/scripts/linters/src/Support/FileFinder.php
new file mode 100644
index 00000000..50dabcd8
--- /dev/null
+++ b/scripts/linters/src/Support/FileFinder.php
@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shirabe\Lint\Support;
+
+final class FileFinder
+{
+    // Returns absolute paths to each crate's Cargo.toml (crates/*/Cargo.toml), sorted.
+    public static function cargoTomls(string $rootDir): array
+    {
+        $paths = glob("{$rootDir}/crates/*/Cargo.toml") ?: [];
+        sort($paths);
+
+        return $paths;
+    }
+
+    /** @return list<string> absolute paths to *.rs files under crates/, sorted */
+    public static function rustFiles(string $rootDir): array
+    {
+        return self::walk("{$rootDir}/crates", static fn (string $path): bool => str_ends_with($path, '.rs'));
+    }
+
+    // Returns absolute paths to mod.rs files under each crate's src/ tree
+    // (crates/*/src/**/mod.rs), sorted.
+    public static function modRsFiles(string $rootDir): array
+    {
+        $found = [];
+
+        foreach (glob("{$rootDir}/crates/*", GLOB_ONLYDIR) ?: [] as $crateDir) {
+            $srcDir = "{$crateDir}/src";
+            if (!is_dir($srcDir)) {
+                continue;
+            }
+
+            foreach (self::walk($srcDir, static fn (string $path): bool => basename($path) === 'mod.rs') as $path) {
+                $found[] = $path;
+            }
+        }
+
+        sort($found);
+
+        return $found;
+    }
+
+    /** @return list<string> */
+    private static function walk(string $baseDir, callable $predicate): array
+    {
+        if (!is_dir($baseDir)) {
+            return [];
+        }
+
+        $found = [];
+        $iterator = new \RecursiveIteratorIterator(
+            new \RecursiveDirectoryIterator($baseDir, \FilesystemIterator::SKIP_DOTS),
+        );
+        foreach ($iterator as $file) {
+            /** @var \SplFileInfo $file */
+            if ($file->isFile() && $predicate($file->getPathname())) {
+                $found[] = $file->getPathname();
+            }
+        }
+
+        sort($found);
+
+        return $found;
+    }
+}