runtime(plugin): unify to Nyash ABI v2 dispatch via shim; loader drops legacy nyash_plugin_invoke and records TypeBox invoke_id; all PluginBoxV2 invoke paths use v2 shim

src/runtime/plugin_loader_v2/enabled/mod.rs

@@ -17,6 +17,32 @@ pub fn metadata_for_type_id(type_id: u32) -> Option<PluginBoxMetadata> {
     guard.metadata_for_type_id(type_id)
 }
 
+/// Resolve per-Box invoke function for a type_id (v2 only)
+pub fn box_invoke_for_type_id(type_id: u32) -> Option<super::enabled::host_bridge::BoxInvokeFn> {
+    let loader = get_global_loader_v2();
+    let guard = loader.read().ok()?;
+    guard.box_invoke_fn_for_type_id(type_id)
+}
+
+/// Library-level shim to dispatch a v2 per-Box invoke function using type_id
+#[no_mangle]
+pub extern "C" fn nyash_plugin_invoke_v2_shim(
+    type_id: u32,
+    method_id: u32,
+    instance_id: u32,
+    args: *const u8,
+    args_len: usize,
+    result: *mut u8,
+    result_len: *mut usize,
+) -> i32 {
+    if let Some(f) = box_invoke_for_type_id(type_id) {
+        // Safety: Plugin-provided function pointer; adhere to C ABI
+        return unsafe { f(instance_id, method_id, args, args_len, result, result_len) };
+    }
+    // E_PLUGIN (-5) when not found
+    -5
+}
+
 pub fn backend_kind() -> &'static str {
     "enabled"
 }