feat(downcast): wire package/repo/filter instanceof checks via existing handle/as_any

Resolve three category-4 TODO(phase-b) placeholders that were short-circuited
to None/true, by routing them through downcast mechanisms that already exist:

- package_sorter: PackageInterfaceHandle::as_root() for the
  instanceof RootPackageInterface check that adds dev-requires
- platform_repository::is_complete_package: as_complete().is_some(),
  consistent with the inlined check already in add_package
- create_project_command: PlatformRequirementFilterInterface::as_any()
  downcast to IgnoreAllPlatformRequirementFilter

No new trait infrastructure introduced.

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

3 files changed, 8 insertions, 10 deletions

diff --git a/crates/shirabe/src/command/create_project_command.rs b/crates/shirabe/src/command/create_project_command.rs
index e52fe39..90a4d99 100644
--- a/crates/shirabe/src/command/create_project_command.rs
+++ b/crates/shirabe/src/command/create_project_command.rs
@@ -830,9 +830,11 @@ impl CreateProjectCommand {
                     format!("stability {}", stability)
                 }
             );
-            // TODO(phase-b): `$platformRequirementFilter instanceof IgnoreAllPlatformRequirementFilter`
-            let is_ignore_all: Option<&IgnoreAllPlatformRequirementFilter> = None;
-            if is_ignore_all.is_none()
+            let is_ignore_all = platform_requirement_filter
+                .as_any()
+                .downcast_ref::<IgnoreAllPlatformRequirementFilter>()
+                .is_some();
+            if !is_ignore_all
                 && version_selector
                     .find_best_candidate(
                         &name,
diff --git a/crates/shirabe/src/repository/platform_repository.rs b/crates/shirabe/src/repository/platform_repository.rs
index b8c4f52..0d10e3a 100644
--- a/crates/shirabe/src/repository/platform_repository.rs
+++ b/crates/shirabe/src/repository/platform_repository.rs
@@ -1903,9 +1903,8 @@ impl PlatformRepository {
 
     // ---- helpers ----
 
-    fn is_complete_package(_package: PackageInterfaceHandle) -> bool {
-        // TODO(phase-b): use Any-style downcasting once the trait carries it.
-        true
+    fn is_complete_package(package: PackageInterfaceHandle) -> bool {
+        package.as_complete().is_some()
     }
 
     fn resource_bundle_get(_value: &PhpMixed, _key: &str) -> PhpMixed {
diff --git a/crates/shirabe/src/util/package_sorter.rs b/crates/shirabe/src/util/package_sorter.rs
index 9db56f5..97b2561 100644
--- a/crates/shirabe/src/util/package_sorter.rs
+++ b/crates/shirabe/src/util/package_sorter.rs
@@ -6,7 +6,6 @@ use shirabe_php_shim::{strnatcasecmp, version_compare};
 use crate::package::Link;
 use crate::package::PackageInterface;
 use crate::package::PackageInterfaceHandle;
-use crate::package::RootPackage;
 
 pub struct PackageSorter;
 
@@ -47,9 +46,7 @@ impl PackageSorter {
 
         for package in &packages {
             let mut links: IndexMap<String, Link> = package.get_requires();
-            // TODO(phase-b): check for RootAliasPackage as well; PackageInterface lacks as_any
-            let root_package: Option<&RootPackage> = None;
-            if let Some(root_package) = root_package {
+            if let Some(root_package) = package.as_root() {
                 links.extend(root_package.get_dev_requires());
             }
             for link in links.values() {