feat(php-shim): give ported exceptions PHP's class hierarchy

Ported exceptions were flat structs reached with `downcast_ref`, so
Composer's `catch (\RuntimeException $e)` only matched the exact leaf
type and `get_class($e)` had nothing to report. Each exception now
embeds an instance of the class it extends and travels inside an
`AnyThrowable`; `Catch::catch`/`catch_mut` walk that chain, and
`PhpClass::php_class_name` yields the PHP FQCN.

Dropping the `std::error::Error` impls from the exception types leaves
`AnyThrowable` as the only route into an `anyhow::Error`, so the walk
cannot be bypassed. A `no_exception_downcast` linter catches the
`downcast::<X>()` calls that would now silently answer `None`.

Three sites change behavior as a result: the `TransportException`
exit-code override reaches `MaxFileSizeExceededException`, the
`catch (\LogicException)` in findSimilar() reaches its subclasses, and
rendered exception titles carry the real class name rather than a
guess. `get_class_err()` is no longer a `todo!()`, which re-enables
FilesystemRepositoryTest::testCorruptedRepositoryFile.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 1 insertions, 5 deletions

diff --git a/crates/shirabe/src/dependency_resolver/rule_set.rs b/crates/shirabe/src/dependency_resolver/rule_set.rs
index f7300d93..50f7cb45 100644
--- a/crates/shirabe/src/dependency_resolver/rule_set.rs
+++ b/crates/shirabe/src/dependency_resolver/rule_set.rs
@@ -59,11 +59,7 @@ impl RuleSet {
     ) -> anyhow::Result<()> {
         let types = Self::types();
         if !types.contains_key(&r#type) {
-            return Err(OutOfBoundsException {
-                message: format!("Unknown rule type: {}", r#type),
-                code: 0,
-            }
-            .into());
+            return Err(OutOfBoundsException::new(format!("Unknown rule type: {}", r#type)).into());
         }
 
         let hash = rule.borrow().get_hash()?.to_string();