refactor(xdebug-handler): extract composer/xdebug_handler into the shirabe-xdebug-handler crate

Move `Composer\XdebugHandler` out of shirabe-external-packages and into
its own crate, so the path is `shirabe_xdebug_handler::XdebugHandler`
instead of
`shirabe_external_packages::composer::xdebug_handler::XdebugHandler`.

Standing alone, the stub no longer sits in a crate that shirabe-php-rpc
depends on, so drop the dependency-cycle rationale from the comments that
explain why callers reach for shirabe_php_rpc directly.

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

2 files changed, 35 insertions, 0 deletions

diff --git a/crates/shirabe-xdebug-handler/src/lib.rs b/crates/shirabe-xdebug-handler/src/lib.rs
new file mode 100644
index 00000000..c95f237d
--- /dev/null
+++ b/crates/shirabe-xdebug-handler/src/lib.rs
@@ -0,0 +1,3 @@
+pub mod xdebug_handler;
+
+pub use xdebug_handler::*;
diff --git a/crates/shirabe-xdebug-handler/src/xdebug_handler.rs b/crates/shirabe-xdebug-handler/src/xdebug_handler.rs
new file mode 100644
index 00000000..6ccedc6a
--- /dev/null
+++ b/crates/shirabe-xdebug-handler/src/xdebug_handler.rs
@@ -0,0 +1,32 @@
+//! ref: composer/vendor/composer/xdebug-handler/src/XdebugHandler.php
+
+#[derive(Debug)]
+pub struct XdebugHandler;
+
+impl XdebugHandler {
+    pub fn is_xdebug_active() -> bool {
+        // TODO(php-runtime)
+        false
+    }
+
+    pub fn get_skipped_version() -> Option<String> {
+        // TODO(php-runtime)
+        // The restart-to-disable-xdebug mechanism is not ported (`is_xdebug_active` is
+        // hardcoded `false`), so a restart never happens and `self::$skipped` stays at
+        // its PHP default of `""`.
+        Some(String::new())
+    }
+
+    pub fn get_all_ini_files() -> Vec<String> {
+        // TODO(php-runtime)
+        // No XdebugHandler is ever constructed (`self::$name` stays null), because the
+        // `new XdebugHandler('Composer'); $xdebug->check();` bootstrap in `bin/composer` is not
+        // ported (see the TODO(phase-c) at the top of shirabe's main.rs), so the
+        // COMPOSER_ORIGINAL_INIS env-var branch is unreachable here.
+        //
+        // Callers that need the real PHP runtime's ini files (php_ini_loaded_file() /
+        // php_ini_scanned_files()) query shirabe_php_rpc directly instead of going through this
+        // stub; see IniHelper::get_all in the shirabe crate.
+        vec![String::new()]
+    }
+}