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, 11 insertions, 17 deletions

diff --git a/crates/shirabe/src/command/audit_command.rs b/crates/shirabe/src/command/audit_command.rs
index 0eee0036..268984d6 100644
--- a/crates/shirabe/src/command/audit_command.rs
+++ b/crates/shirabe/src/command/audit_command.rs
@@ -60,10 +60,7 @@ impl AuditCommand {
             let locker = composer.get_locker().clone();
             let mut locker = locker.borrow_mut();
             if !locker.is_locked() {
-                return Err(UnexpectedValueException {
-                    message: "Valid composer.json and composer.lock files are required to run this command with --locked".to_string(),
-                    code: 0,
-                }.into());
+                return Err(UnexpectedValueException::new("Valid composer.json and composer.lock files are required to run this command with --locked".to_string()).into());
             }
             let locked_repo = locker.get_locked_repository(
                 !input
@@ -228,19 +225,16 @@ impl Command for AuditCommand {
                     .collect::<Vec<_>>(),
             )
         {
-            return Err(InvalidArgumentException {
-                message: format!(
-                    "--abandoned must be one of {}.",
-                    implode(
-                        ", ",
-                        &Auditor::ABANDONEDS
-                            .iter()
-                            .map(|s| s.to_string())
-                            .collect::<Vec<_>>()
-                    )
-                ),
-                code: 0,
-            }
+            return Err(InvalidArgumentException::new(format!(
+                "--abandoned must be one of {}.",
+                implode(
+                    ", ",
+                    &Auditor::ABANDONEDS
+                        .iter()
+                        .map(|s| s.to_string())
+                        .collect::<Vec<_>>()
+                )
+            ))
             .into());
         }