fix(dependency-resolver): query real PHP for ext-* version/loaded checks

Two shim gaps made the extension-related branches of solver-problem
messages wrong:

- phpversion($ext) with a non-empty extension can't be known statically
  (it's shirabe-php-shim's todo!()); Problem::get_missing_package_reason
  now calls shirabe_php_rpc::phpversion, the same RPC bridge
  platform::runtime::Runtime::get_extension_version already uses.
- extension_loaded's hardcoded allowlist was missing "pcre", a mandatory
  always-compiled-in PHP extension, so ext-pcre was misreported as
  "missing from your system" instead of "disabled by your platform
  config" whenever a platform override disabled it.

Also fix XdebugHandler::getAllIniFiles() always returning `[""]`
(a php-runtime stub): create_extension_hint()'s early-return guard
(`paths[0] empty && len==1`) fired unconditionally, silently dropping
the entire "To enable extensions..." hint from every solver-problem
message that mentions missing extensions. shirabe-external-packages
can't depend on shirabe-php-rpc (shirabe-php-rpc already depends on
shirabe-external-packages), so IniHelper::get_all() queries a new
get_all_ini_files RPC command directly instead of going through the
stub.

This exposed that XdebugHandler is never constructed with a name
because bin/composer's restart-without-Xdebug bootstrap was never
ported to main.rs, making COMPOSER_ORIGINAL_INIS-driven behavior
unreachable; documented with a TODO(phase-c) and updated
ini_helper_test.rs's ignore reasons (and ignored test_with_no_ini,
which only passed before by coincidence with the old stub's constant
output) to match.

1 files changed, 10 insertions, 4 deletions

diff --git a/crates/shirabe-external-packages/src/composer/xdebug_handler/xdebug_handler.rs b/crates/shirabe-external-packages/src/composer/xdebug_handler/xdebug_handler.rs
index 01f8eb78..3bbe9014 100644
--- a/crates/shirabe-external-packages/src/composer/xdebug_handler/xdebug_handler.rs
+++ b/crates/shirabe-external-packages/src/composer/xdebug_handler/xdebug_handler.rs
@@ -19,10 +19,16 @@ impl XdebugHandler {
 
     pub fn get_all_ini_files() -> Vec<String> {
         // TODO(php-runtime)
-        // No XdebugHandler is ever constructed (`self::$name` stays null) so the
-        // COMPOSER_ORIG_INIS env lookup is skipped, and without a PHP runtime
-        // `php_ini_loaded_file()` is `false` and `php_ini_scanned_files()` is `false`,
-        // so PHP would return `[(string) false]` = `[""]`.
+        // No XdebugHandler is ever constructed (`self::$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.
+        //
+        // shirabe-external-packages cannot depend on shirabe-php-rpc (the reverse dependency
+        // would cycle, since shirabe-php-rpc already depends on shirabe-external-packages), so
+        // 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 crate::util::ini_helper::IniHelper::get_all.
         vec![String::new()]
     }
 }