feat(plugin): guard Rust-owned classes the worker has no proxy for

The worker's autoloader fell through to the real Composer source for every
Rust-owned FQCN without a proxy stub, so plugin code doing `new Filesystem()`
or subclassing `LibraryInstaller` silently ran on a second instance the Rust
side never sees. An unimplemented part of the plugin API has to fail with an
explicit error naming it, not quietly work on a disconnected copy.

The stub generator now emits a guard class for each of those FQCNs: the real
declaration, hierarchy and constants, with every constructor and method
raising an explicit error. References satisfied by the declaration alone
(`instanceof`, `X::class`, `Link::TYPE_REQUIRE`) keep working. Two FQCNs stay
resolvable to the real class, each listed with the worker-side mechanism that
makes a natively constructed instance correct.

The error had nowhere to go: `Installer::run` dropped the `Result` of both
`dispatch_script` calls, so an exception from a listener ended in exit 0.
Both propagate now, the way the exception does upstream.

Three real-plugin E2E comparisons stop at a guard and are ignored, each
naming the class it needs.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/crates/shirabe-php-rpc/php/guards/Composer/DependencyResolver/RuleSet.php b/crates/shirabe-php-rpc/php/guards/Composer/DependencyResolver/RuleSet.php
new file mode 100644
index 00000000..40d6780a
--- /dev/null
+++ b/crates/shirabe-php-rpc/php/guards/Composer/DependencyResolver/RuleSet.php
@@ -0,0 +1,78 @@
+<?php
+
+// Generated by scripts/plugin-stub-generator; do not edit by hand.
+// Guard for Composer\DependencyResolver\RuleSet.
+// The Rust side owns this class and the worker has no proxy for it, so this
+// declaration shadows the real one: the constants and the hierarchy stay, while
+// constructing it or calling anything on it raises an explicit error.
+
+namespace Composer\DependencyResolver;
+
+use Composer\Repository\RepositorySet;
+
+class RuleSet implements \IteratorAggregate, \Countable
+{
+    public const TYPE_PACKAGE = 0;
+    public const TYPE_REQUEST = 1;
+    public const TYPE_LEARNED = 4;
+    public const TYPES = [
+        self::TYPE_PACKAGE => 'PACKAGE',
+        self::TYPE_REQUEST => 'REQUEST',
+        self::TYPE_LEARNED => 'LEARNED',
+    ];
+
+    public function __construct()
+    {
+        \ShirabeUnsupportedClass::fail(self::class, '__construct');
+    }
+
+    public function add(Rule $rule, $type): void
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'add');
+    }
+
+    public function count(): int
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'count');
+    }
+
+    public function ruleById(int $id): Rule
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'ruleById');
+    }
+
+    public function getRules(): array
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'getRules');
+    }
+
+    public function getIterator(): RuleSetIterator
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'getIterator');
+    }
+
+    public function getIteratorFor($types): RuleSetIterator
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'getIteratorFor');
+    }
+
+    public function getIteratorWithout($types): RuleSetIterator
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'getIteratorWithout');
+    }
+
+    public function getTypes(): array
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'getTypes');
+    }
+
+    public function getPrettyString(?RepositorySet $repositorySet = null, ?Request $request = null, ?Pool $pool = null, bool $isVerbose = false): string
+    {
+        \ShirabeUnsupportedClass::fail(self::class, 'getPrettyString');
+    }
+
+    public function __toString(): string
+    {
+        \ShirabeUnsupportedClass::fail(self::class, '__toString');
+    }
+}