feat(php-rpc): query real PHP version and binary for --version

Add a minimal shirabe-php-rpc crate that spawns the system PHP as a
child process and asks it for runtime information over a Unix domain
socket, then use it to fill the `--version` PHP line with the real
\PHP_VERSION and \PHP_BINARY instead of fixed placeholder values.

See docs/dev/php-rpc.md for the design and scope.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/crates/shirabe-php-rpc/php/worker.php b/crates/shirabe-php-rpc/php/worker.php
new file mode 100644
index 0000000..214817a
--- /dev/null
+++ b/crates/shirabe-php-rpc/php/worker.php
@@ -0,0 +1,37 @@
+<?php
+
+// PHP glue worker. See docs/dev/php-rpc.md.
+
+$client = @stream_socket_client('unix://' . $argv[1], $errno, $errstr);
+if ($client === false) {
+    exit(1);
+}
+$dispatch = [
+    'get_php_version' => static fn() => PHP_VERSION,
+    'get_php_binary'  => static fn() => PHP_BINARY,
+];
+$read_exact = static function ($conn, int $len): ?string {
+    $buf = '';
+    while (strlen($buf) < $len) {
+        $chunk = fread($conn, $len - strlen($buf));
+        if ($chunk === false || $chunk === '') {
+            return null;
+        }
+        $buf .= $chunk;
+    }
+    return $buf;
+};
+while (true) {
+    $header = $read_exact($client, 8);
+    if ($header === null) {
+        break;
+    }
+    $len = unpack('P', $header)[1];
+    $name = $len === 0 ? '' : $read_exact($client, $len);
+    if ($name === null) {
+        break;
+    }
+    $result = isset($dispatch[$name]) ? ($dispatch[$name])() : null;
+    $payload = serialize($result);
+    fwrite($client, pack('P', strlen($payload)) . $payload);
+}