refactor(io): model ask_and_validate validators with anyhow::Result

PHP's askAndValidate throws when a validator rejects input. Change the
IOInterface validator callback and return type to anyhow::Result so the
call sites can return Err instead of panic, faithfully modeling the throw
semantics already supported by the Question layer.

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

1 files changed, 2 insertions, 2 deletions

diff --git a/crates/shirabe/src/io/buffer_io.rs b/crates/shirabe/src/io/buffer_io.rs
index 291b64b..836fd95 100644
--- a/crates/shirabe/src/io/buffer_io.rs
+++ b/crates/shirabe/src/io/buffer_io.rs
@@ -175,10 +175,10 @@ impl crate::io::IOInterfaceImmutable for BufferIO {
     fn ask_and_validate(
         &self,
         question: String,
-        validator: Box<dyn Fn(PhpMixed) -> PhpMixed>,
+        validator: Box<dyn Fn(PhpMixed) -> anyhow::Result<PhpMixed>>,
         attempts: Option<i64>,
         default: PhpMixed,
-    ) -> PhpMixed {
+    ) -> anyhow::Result<PhpMixed> {
         self.inner
             .ask_and_validate(question, validator, attempts, default)
     }