Fix IntelliJ IDEA project open silent failure by removing FlutterProjectOpenProcessor

FlutterProjectOpenProcessor silently failed to open Flutter projects
without a .idea directory because getDelegateImportProvider() returned
null when no other processor could claim the project. Since this
processor was registered with order="first", no fallback occurred.

Apply the same fix pattern as PR flutter#8710 (Android Studio):
- Remove FlutterProjectOpenProcessor.kt
- Remove its <projectOpenProcessor> registration from plugin.xml
- Add module-type-fixing logic to FlutterInitializer (startup activity)

This lets the platform's default project opener handle opening, then
FlutterInitializer configures Flutter module type and Dart SDK after
the project is loaded.

Fixes flutter#8845

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

resources/META-INF/plugin.xml

@@ -335,8 +335,6 @@
     <!-- See https://github.com/flutter/flutter-intellij/issues/8029 -->
     <projectService serviceImplementation="io.flutter.view.InspectorView" overrides="false"/>
 
-    <projectOpenProcessor id="flutter" implementation="io.flutter.project.FlutterProjectOpenProcessor" order="first"/>
-
     <editorNotificationProvider implementation="io.flutter.editor.FlutterPubspecNotificationProvider"/>
     <editorNotificationProvider implementation="io.flutter.inspections.SdkConfigurationNotificationProvider"/>
     <editorNotificationProvider implementation="io.flutter.editor.NativeEditorNotificationProvider"/>

src/io/flutter/FlutterInitializer.java

@@ -67,8 +67,6 @@
  * Runs actions after the project has started up and the index is up to date.
  *
  * @see ProjectOpenActivity for actions that run earlier.
- * @see io.flutter.project.FlutterProjectOpenProcessor for additional actions that
- * may run when a project is being imported.
  */
 public class FlutterInitializer extends FlutterProjectActivity {
   private boolean toolWindowsInitialized = false;
@@ -97,6 +95,18 @@ public void executeProjectStartup(@NotNull Project project) {
     // Start a DevTools server
     DevToolsService.getInstance(project);
 
+    // Ensure Flutter project configuration is applied for projects that may have been
+    // opened without a .idea directory. Previously this was handled by FlutterProjectOpenProcessor,
+    // but that processor silently failed when no delegate processor could open the project.
+    // Instead, we let the platform open the project normally and apply our configuration here.
+    // See https://github.com/flutter/flutter-intellij/issues/8661 (Android Studio equivalent)
+    for (Module module : FlutterModuleUtils.getModules(project)) {
+      if (FlutterModuleUtils.declaresFlutter(module) && !FlutterModuleUtils.isFlutterModule(module)) {
+        log().info("Fixing Flutter module configuration for " + module.getName());
+        FlutterModuleUtils.setFlutterModuleAndReload(module, project);
+      }
+    }
+
     // If the project declares a Flutter dependency, do some extra initialization.
     boolean hasFlutterModule = false;