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.

2 files changed, 20 insertions, 0 deletions

diff --git a/crates/shirabe-php-rpc/php/worker.php b/crates/shirabe-php-rpc/php/worker.php
index d7d8f251..060373d5 100644
--- a/crates/shirabe-php-rpc/php/worker.php
+++ b/crates/shirabe-php-rpc/php/worker.php
@@ -13,6 +13,14 @@ $dispatch = [
     'curl_version' => static fn($arg) => function_exists('curl_version') ? (curl_version()['version'] ?? null) : null,
     'phpversion' => static fn($name) => phpversion($name),
     'get_loaded_extensions' => static fn($arg) => implode(',', get_loaded_extensions()),
+    'get_all_ini_files' => static function ($arg) {
+        $paths = [(string) php_ini_loaded_file()];
+        $scanned = php_ini_scanned_files();
+        if ($scanned !== false) {
+            $paths = array_merge($paths, array_map('trim', explode(',', $scanned)));
+        }
+        return implode(',', $paths);
+    },
     'extension_info' => static function ($name) {
         if (!extension_loaded($name)) {
             return '';
diff --git a/crates/shirabe-php-rpc/src/lib.rs b/crates/shirabe-php-rpc/src/lib.rs
index d939829a..dde91d3c 100644
--- a/crates/shirabe-php-rpc/src/lib.rs
+++ b/crates/shirabe-php-rpc/src/lib.rs
@@ -88,6 +88,18 @@ pub fn get_loaded_extensions() -> Vec<String> {
     }
 }
 
+/// `Composer\XdebugHandler\XdebugHandler::getAllIniFiles()` (minus the `self::$name` branch,
+/// which is unreachable since this port never constructs an XdebugHandler): `[(string)
+/// php_ini_loaded_file()]` merged with the trimmed, comma-split `php_ini_scanned_files()` list
+/// when scanning is active. Paths are joined with `,` on the PHP side and split back here; real
+/// ini paths never contain a comma (same assumption `get_loaded_extensions` makes).
+pub fn get_all_ini_files() -> Vec<String> {
+    match call("get_all_ini_files", "") {
+        PhpMixed::String(s) => s.split(',').map(|s| s.to_string()).collect(),
+        other => panic!("PHP RPC: `get_all_ini_files` did not return a string: {other:?}"),
+    }
+}
+
 const GLUE_SCRIPT: &str = include_str!("../php/worker.php");
 
 struct Worker {