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, 4 insertions, 7 deletions

diff --git a/crates/shirabe-php-shim/src/zip.rs b/crates/shirabe-php-shim/src/zip.rs
index 6a088419..7284b029 100644
--- a/crates/shirabe-php-shim/src/zip.rs
+++ b/crates/shirabe-php-shim/src/zip.rs
@@ -146,13 +146,10 @@ impl ZipArchive {
 
     pub fn extract_to(&self, path: impl AsRef<std::path::Path>) -> Result<bool, ErrorException> {
         if let Some(mock) = &self.mock {
-            return mock.extract_to.clone().map_err(|message| ErrorException {
-                message,
-                code: 0,
-                severity: 1,
-                filename: String::new(),
-                lineno: 0,
-            });
+            return mock
+                .extract_to
+                .clone()
+                .map_err(|message| ErrorException::new(message, 0, 1, String::new(), 0, None));
         }
         let mut state = self.state.borrow_mut();
         let ZipState::Reader(archive) = &mut *state else {