feat(php-shim): model $_ENV/$_SERVER as OsString snapshots

Rework the environment shim around getenv/putenv on the real environment
and $_ENV/$_SERVER as startup snapshots, all over OsString. Migrate every
caller off the old server()/server_argv() helpers and force the snapshots
in main() before any putenv() runs. Document the porting rules in
docs/dev/env-vars-porting.md.

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

1 files changed, 4 insertions, 6 deletions

diff --git a/crates/shirabe/tests/util/ini_helper_test.rs b/crates/shirabe/tests/util/ini_helper_test.rs
index f511d76..d1e2071 100644
--- a/crates/shirabe/tests/util/ini_helper_test.rs
+++ b/crates/shirabe/tests/util/ini_helper_test.rs
@@ -12,7 +12,8 @@ fn set_up() -> TearDown {
     // XdebugHandler is a unit struct with no name-registration API, so this
     // step is a no-op here.
     // Save current state
-    let env_original = getenv("COMPOSER_ORIGINAL_INIS");
+    let env_original =
+        getenv("COMPOSER_ORIGINAL_INIS").map(|value| value.to_string_lossy().into_owned());
     TearDown { env_original }
 }
 
@@ -20,7 +21,7 @@ fn set_up() -> TearDown {
 fn tear_down(env_original: &Option<String>) {
     // Restore original state
     if let Some(env_original) = env_original {
-        putenv(&format!("COMPOSER_ORIGINAL_INIS={env_original}"));
+        unsafe { putenv("COMPOSER_ORIGINAL_INIS", env_original) };
     } else {
         Platform::clear_env("COMPOSER_ORIGINAL_INIS");
     }
@@ -38,10 +39,7 @@ impl Drop for TearDown {
 }
 
 fn set_env(paths: &[&str]) {
-    putenv(&format!(
-        "COMPOSER_ORIGINAL_INIS={}",
-        paths.join(PATH_SEPARATOR)
-    ));
+    unsafe { putenv("COMPOSER_ORIGINAL_INIS", paths.join(PATH_SEPARATOR)) };
 }
 
 #[test]