feat(console): implement StringInput stringification in global proxy

StringInput inherits __toString from ArgvInput in PHP; mirror that with a
Display impl delegating to its inner ArgvInput, and use it in
GlobalCommand::input_to_string.

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

1 files changed, 2 insertions, 4 deletions

diff --git a/crates/shirabe/src/command/global_command.rs b/crates/shirabe/src/command/global_command.rs
index 5769ebb..27331a7 100644
--- a/crates/shirabe/src/command/global_command.rs
+++ b/crates/shirabe/src/command/global_command.rs
@@ -53,10 +53,8 @@ impl GlobalCommand {
             Ok(argv_input.to_string())
         } else if let Some(array_input) = input_any.downcast_ref::<ArrayInput>() {
             Ok(array_input.to_string())
-        } else if input_any.is::<StringInput>() {
-            // StringInput's stringification is not exposed by shirabe-external-packages
-            // (its inner ArgvInput is pub(crate) and it defines no public __toString).
-            todo!("StringInput::__toString is not accessible from the shirabe crate")
+        } else if let Some(string_input) = input_any.downcast_ref::<StringInput>() {
+            Ok(string_input.to_string())
         } else {
             Err(LogicException {
                 message: "Expected an Input instance that is stringable".to_string(),