feat(plugin): carry an exception's class and state across the boundary

A Rust-side failure reached plugin code as a RuntimeException whose message
carried the name of the call that failed, so `catch (TransportException $e)`
never matched and the status code the plugin branches on was gone.

The Throw frame now names the class the exception was thrown as and carries
the state that class declares beyond message and code.
\Shirabe\MaterializedThrowable rebuilds it in the child: `new $class($message,
$code)` for a class whose constructor has \Exception's shape, then the
properties by reflection. A class the child cannot build that way keeps the
RuntimeException shape.

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

1 files changed, 10 insertions, 5 deletions

diff --git a/crates/shirabe-php-rpc/php/worker.php b/crates/shirabe-php-rpc/php/worker.php
index bc10c2de..defa4fb5 100644
--- a/crates/shirabe-php-rpc/php/worker.php
+++ b/crates/shirabe-php-rpc/php/worker.php
@@ -337,10 +337,13 @@ final class ShirabeRpcRuntime
                     $outParams = self::fromWire($fields[1] ?? []);
                     return self::fromWire($fields[0]);
                 }
-                [$class, $message, $code] = $fields;
-                // TODO(plugin): reconstruct the original exception class instead of collapsing
-                // everything to RuntimeException.
-                throw new RuntimeException($message, (int) $code);
+                [$class, $message, $code, $properties] = $fields;
+                throw \Shirabe\MaterializedThrowable::revive(
+                    $class,
+                    $message,
+                    (int) $code,
+                    self::fromWire($properties)
+                );
             }
             self::dispatchRequest($tag, $inId, $payload);
         }
@@ -435,7 +438,9 @@ final class ShirabeRpcRuntime
             self::writeFrame(
                 SHIRABE_TAG_THROW,
                 $corrId,
-                serialize([get_class($e), $e->getMessage(), (int) $e->getCode()])
+                // TODO(plugin): the properties field is empty in this direction; no Rust-side
+                // consumer rebuilds a ported exception from a Throw frame yet.
+                serialize([get_class($e), $e->getMessage(), (int) $e->getCode(), []])
             );
         }
     }