feat(phase-c): resolve &mut-access phase-b TODOs via handle setters

PHP mutator methods that the Phase B port could not call because only
&self / &dyn / Rc access was available. Resolved by the interior-mutation
APIs that already exist: handle &self setters (set_dist/source_reference,
set_requires/dev/references/stability_flags), Rc<RefCell<dyn InputInterface>>
.borrow_mut(), and get_installation_manager().borrow_mut() (build_package_map
passes an empty/canonical package list per upstream). composer.get_package()
returns &RootPackageInterfaceHandle, so the "&dyn" Phase B note was wrong.
factory's set_config_source/set_auth_config_source were already live code;
their stale TODOs are removed.

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

1 files changed, 5 insertions, 4 deletions

diff --git a/crates/shirabe/src/command/show_command.rs b/crates/shirabe/src/command/show_command.rs
index 53f3ac4..f324a5c 100644
--- a/crates/shirabe/src/command/show_command.rs
+++ b/crates/shirabe/src/command/show_command.rs
@@ -634,10 +634,11 @@ impl ShowCommand {
                 self.get_io().write_no_newline(&package.get_name());
                 let path = {
                     let composer_ref = composer.as_ref().unwrap();
-                    // TODO(phase-b): get_installation_manager wants &mut Composer; PHP shares
-                    // by reference. Skipping the install path lookup keeps compile clean.
-                    let _ = composer_ref;
-                    None::<String>
+                    composer_ref
+                        .borrow_partial()
+                        .get_installation_manager()
+                        .borrow_mut()
+                        .get_install_path(package.clone().into())
                 };
                 if let Some(path) = path {
                     let real = realpath(&path).unwrap_or_default();