fix(self-update-command): resolve finder-related phase-b TODOs

- Add Display for SplFileInfo (PHP (string) cast -> getPathname) and use it
  in clean_backups instead of a debug-format placeholder.
- Generalize iterator_to_array's signature to preserve the element type so
  get_last_backup_version collects real SplFileInfo and returns the last
  basename, instead of mapping every entry to PhpMixed::Null.
- Drop the stale builder-restructure TODO in get_old_installation_finder.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

3 files changed, 13 insertions, 16 deletions

diff --git a/crates/shirabe-external-packages/src/symfony/component/finder/spl_file_info.rs b/crates/shirabe-external-packages/src/symfony/component/finder/spl_file_info.rs
index 31a0e50..3c1be6d 100644
--- a/crates/shirabe-external-packages/src/symfony/component/finder/spl_file_info.rs
+++ b/crates/shirabe-external-packages/src/symfony/component/finder/spl_file_info.rs
@@ -1,6 +1,12 @@
 #[derive(Debug)]
 pub struct SplFileInfo;
 
+impl std::fmt::Display for SplFileInfo {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.get_pathname())
+    }
+}
+
 impl SplFileInfo {
     pub fn new(_path: &str) -> Self {
         todo!()
diff --git a/crates/shirabe-php-shim/src/lib.rs b/crates/shirabe-php-shim/src/lib.rs
index acc81d9..e87cd2d 100644
--- a/crates/shirabe-php-shim/src/lib.rs
+++ b/crates/shirabe-php-shim/src/lib.rs
@@ -1486,9 +1486,9 @@ pub fn openssl_free_key(_key: PhpMixed) {
     todo!()
 }
 
-pub fn iterator_to_array<T>(_iter: T) -> Vec<PhpMixed>
+pub fn iterator_to_array<I>(iter: I) -> Vec<I::Item>
 where
-    T: IntoIterator<Item = PhpMixed>,
+    I: IntoIterator,
 {
     todo!()
 }
diff --git a/crates/shirabe/src/command/self_update_command.rs b/crates/shirabe/src/command/self_update_command.rs
index 63e6a0c..1dc8d87 100644
--- a/crates/shirabe/src/command/self_update_command.rs
+++ b/crates/shirabe/src/command/self_update_command.rs
@@ -976,8 +976,7 @@ RGv89BPD+2DLnJysngsvVaUCAwEAAQ==\n\
             if file.get_basename(Some(Self::OLD_INSTALL_EXT)) == except.unwrap_or_default() {
                 continue;
             }
-            // TODO(phase-b): SplFileInfo to string conversion (PHP __toString returns the path)
-            let file_str = format!("{:?}", file);
+            let file_str = file.to_string();
             io.write_error3(
                 &format!("<info>Removing: {}</info>", file_str),
                 true,
@@ -990,21 +989,13 @@ RGv89BPD+2DLnJysngsvVaUCAwEAAQ==\n\
     pub(crate) fn get_last_backup_version(&self, rollback_dir: &str) -> Option<String> {
         let mut finder = self.get_old_installation_finder(rollback_dir);
         finder.sort_by_name();
-        // TODO(phase-b): iterator_to_array → Vec<PhpMixed>; PHP end() returns last value
-        let files = iterator_to_array(finder.into_iter().map(|_| PhpMixed::Null));
-
-        if (files.len() as i64) > 0 {
-            let last_file = files.last().cloned();
-            return last_file
-                // PHP: end($files)->getBasename(self::OLD_INSTALL_EXT)
-                .and_then(|f| f.as_string().map(|s| s.to_string()));
-        }
-
-        None
+        let files = iterator_to_array(finder);
+        files
+            .last()
+            .map(|f| f.get_basename(Some(Self::OLD_INSTALL_EXT)))
     }
 
     pub(crate) fn get_old_installation_finder(&self, rollback_dir: &str) -> Finder {
-        // TODO(phase-b): builder returns &mut Self; restructure to return owned Finder
         let mut finder = Finder::create();
         finder
             .depth(0)