feat(php-rpc): rework the RPC channel into the tagged plugin protocol

Replace the name\0arg framing with the plugin wire protocol: tagged
frames with corr_id multiplexing, a MAX_FRAME_LEN bound, a thread-ID
based reentrant SessionLock, and the PluginValue codec (encoder plus
the first recursive decoder, iterative with a 512-level depth cap).
Float formatting is ported from php-src into shirabe-php-src so the
encoder is byte-compatible with serialize() under serialize_precision=-1,
which the spawned worker now pins. The worker gains a standing dispatch
loop, CallRustMethod reentrancy, hand-written Event proxy stubs, and
explicit-error answers for everything not implemented yet. The public
query API (get_php_version and friends) is unchanged and now rides the
new protocol; the codec is verified against real PHP by roundtrip
oracle tests covering floats, non-UTF-8 bytes and deep nesting.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

2 files changed, 96 insertions, 0 deletions

diff --git a/crates/shirabe-php-rpc/php/stubs/Composer/EventDispatcher/Event.php b/crates/shirabe-php-rpc/php/stubs/Composer/EventDispatcher/Event.php
new file mode 100644
index 00000000..9ce9c12f
--- /dev/null
+++ b/crates/shirabe-php-rpc/php/stubs/Composer/EventDispatcher/Event.php
@@ -0,0 +1,59 @@
+<?php
+
+// Hand-written proxy stub for Composer\EventDispatcher\Event, kept in the shape the future stub
+// generator will output: the real public methods, each forwarding to the Rust-side entity.
+
+namespace Composer\EventDispatcher;
+
+class Event implements \ShirabeRustStub
+{
+    /** @var int */
+    protected $__rhandle;
+    /** @var int */
+    protected $__epoch;
+
+    public function __construct(int $rhandle, int $epoch)
+    {
+        $this->__rhandle = $rhandle;
+        $this->__epoch = $epoch;
+    }
+
+    public function __destruct()
+    {
+        \ShirabeRustObjectRegistry::release($this->__rhandle);
+    }
+
+    public function __shirabeRustHandleDescriptor(): array
+    {
+        return [
+            '__rhandle' => $this->__rhandle,
+            '__class' => static::class,
+            '__epoch' => $this->__epoch,
+        ];
+    }
+
+    public function getName(): string
+    {
+        return \ShirabeRpcRuntime::callRust($this->__rhandle, 'getName', []);
+    }
+
+    public function getArguments(): array
+    {
+        return \ShirabeRpcRuntime::callRust($this->__rhandle, 'getArguments', []);
+    }
+
+    public function getFlags(): array
+    {
+        return \ShirabeRpcRuntime::callRust($this->__rhandle, 'getFlags', []);
+    }
+
+    public function isPropagationStopped(): bool
+    {
+        return \ShirabeRpcRuntime::callRust($this->__rhandle, 'isPropagationStopped', []);
+    }
+
+    public function stopPropagation(): void
+    {
+        \ShirabeRpcRuntime::callRust($this->__rhandle, 'stopPropagation', []);
+    }
+}
diff --git a/crates/shirabe-php-rpc/php/stubs/Composer/Script/Event.php b/crates/shirabe-php-rpc/php/stubs/Composer/Script/Event.php
new file mode 100644
index 00000000..80afe1b7
--- /dev/null
+++ b/crates/shirabe-php-rpc/php/stubs/Composer/Script/Event.php
@@ -0,0 +1,37 @@
+<?php
+
+// Hand-written proxy stub for Composer\Script\Event, kept in the shape the future stub
+// generator will output. See Composer/EventDispatcher/Event.php.
+
+namespace Composer\Script;
+
+use Composer\EventDispatcher\Event as BaseEvent;
+
+class Event extends BaseEvent
+{
+    public function getComposer(): \Composer\Composer
+    {
+        return \ShirabeRpcRuntime::callRust($this->__rhandle, 'getComposer', []);
+    }
+
+    public function getIO(): \Composer\IO\IOInterface
+    {
+        return \ShirabeRpcRuntime::callRust($this->__rhandle, 'getIO', []);
+    }
+
+    public function isDevMode(): bool
+    {
+        return \ShirabeRpcRuntime::callRust($this->__rhandle, 'isDevMode', []);
+    }
+
+    public function getOriginatingEvent(): ?BaseEvent
+    {
+        return \ShirabeRpcRuntime::callRust($this->__rhandle, 'getOriginatingEvent', []);
+    }
+
+    public function setOriginatingEvent(BaseEvent $event): self
+    {
+        \ShirabeRpcRuntime::callRust($this->__rhandle, 'setOriginatingEvent', [$event]);
+        return $this;
+    }
+}