feat(console): import scripts Command classes as application commands

`Application::do_run` registers a `composer.json` script whose value names a
`Symfony\Component\Console\Command\Command` subclass as a live command. The
class checks and `new $dummy($script)` need a real PHP runtime, so they run in
the worker: the command object lives there and this side keeps a metadata
mirror for `list`/`help`, forwarding a run to the worker-side console
application it is added to. The name and description fixups are applied to the
worker-side object, so both sides carry the same values.

Loading the Composer PHP runtime into the worker is gated on the Rust-side
`ClassLoader`s resolving the class to a file, keeping that load out of every
run whose scripts are plain shell commands.

The worker-side console application handoff now accepts commands registered
after it was published, since the scripts scan runs after plugin commands are
collected. Whether it was published is tracked per application: the handoff is
process-wide, so a second application must replace it rather than extend it.

`shirabe_php_shim::is_subclass_of` has no callers left.

1 files changed, 23 insertions, 0 deletions

diff --git a/crates/shirabe/tests/plugin/fixtures/e2e-script-command/composer.json b/crates/shirabe/tests/plugin/fixtures/e2e-script-command/composer.json
new file mode 100644
index 00000000..2eeff25b
--- /dev/null
+++ b/crates/shirabe/tests/plugin/fixtures/e2e-script-command/composer.json
@@ -0,0 +1,23 @@
+{
+    "name": "shirabe/e2e-script-command",
+    "description": "E2E fixture project: composer.json scripts naming Command classes, run against upstream Composer and Shirabe.",
+    "autoload": {
+        "psr-4": {
+            "ShirabeTest\\ScriptCommand\\": "src/"
+        }
+    },
+    "scripts": {
+        "greet": "ShirabeTest\\ScriptCommand\\GreetCommand",
+        "renamed": "ShirabeTest\\ScriptCommand\\MismatchedNameCommand",
+        "single": "ShirabeTest\\ScriptCommand\\SingleAppCommand",
+        "plain": "echo plain-script"
+    },
+    "scripts-descriptions": {
+        "renamed": "Description taken from composer.json"
+    },
+    "repositories": [
+        {
+            "packagist.org": false
+        }
+    ]
+}