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, 83 insertions, 0 deletions

diff --git a/scripts/linters/src/Linters/CargoWorkspaceDependencies.php b/scripts/linters/src/Linters/CargoWorkspaceDependencies.php
new file mode 100644
index 00000000..3ad86b6f
--- /dev/null
+++ b/scripts/linters/src/Linters/CargoWorkspaceDependencies.php
@@ -0,0 +1,83 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shirabe\Lint\Linters;
+
+use Shirabe\Lint\Linter;
+use Shirabe\Lint\Support\FileFinder;
+use Shirabe\Lint\Support\Paths;
+
+final class CargoWorkspaceDependencies implements Linter
+{
+    private const SECTION_NAMES = ['dependencies', 'dev-dependencies', 'build-dependencies'];
+
+    public function name(): string
+    {
+        return 'cargo_workspace_dependencies';
+    }
+
+    public function failureIntro(): string
+    {
+        return "Found `[dependencies]` / `[dev-dependencies]` entries that do not use `workspace = true`.\n"
+            . 'In a crate `Cargo.toml`, only `name.workspace = true` or `name = { workspace = true, ... }` is allowed:';
+    }
+
+    public function check(string $rootDir, array $excludes): array
+    {
+        $errors = [];
+
+        foreach (FileFinder::cargoTomls($rootDir) as $path) {
+            $relative = Paths::relativeTo($rootDir, $path);
+            if (in_array($relative, $excludes, true)) {
+                continue;
+            }
+
+            array_push($errors, ...$this->findNonWorkspaceDeps($path, $relative));
+        }
+
+        return $errors;
+    }
+
+    /** @return list<string> */
+    private function findNonWorkspaceDeps(string $path, string $relative): array
+    {
+        $errors = [];
+        $currentSection = null;
+
+        foreach (file($path) as $idx => $rawLine) {
+            $stripped = trim($rawLine);
+
+            if (preg_match('/\A\[([^\]]+)\]\z/', $stripped, $m)) {
+                $currentSection = $m[1];
+                continue;
+            }
+
+            if ($currentSection === null || !in_array($currentSection, self::SECTION_NAMES, true)) {
+                continue;
+            }
+            if ($stripped === '' || str_starts_with($stripped, '#')) {
+                continue;
+            }
+
+            if (preg_match('/\A([A-Za-z0-9_-]+)\.workspace\s*=\s*true\b/', $stripped)) {
+                continue;
+            }
+
+            if (preg_match('/\A([A-Za-z0-9_-]+)\s*=\s*\{(.+)\}\s*\z/', $stripped, $m)) {
+                [, $name, $inner] = $m;
+                if (preg_match('/\bworkspace\s*=\s*true\b/', $inner)) {
+                    continue;
+                }
+                $errors[] = "{$relative}:" . ($idx + 1) . ": `{$name}` does not use `workspace = true`";
+                continue;
+            }
+
+            if (preg_match('/\A([A-Za-z0-9_-]+)\s*=/', $stripped, $m)) {
+                $errors[] = "{$relative}:" . ($idx + 1) . ": `{$m[1]}` does not use `workspace = true`";
+            }
+        }
+
+        return $errors;
+    }
+}