refactor(post): remove now-dead PostAction::AlreadyPublished

UpdatePost::execute used to return AlreadyPublished for the Published
short-circuit. This PR widened the short-circuit to four terminal
statuses and consolidated them under PostAction::Finalized — so the
old enum case stopped being emitted, and every caller already had a
defensive in_array([AlreadyPublished, Finalized], ...).

Audit before removal: nothing emits AlreadyPublished anymore (only
UpdatePost::execute returns Actions, and it returns Finalized for
the whole terminal set), no test references the case, and no string
'already_published' exists elsewhere in app/resources/tests/lang.

- Drop the enum case
- Simplify the three in_array checks to a direct === Finalized
- Delete the dead App/PostController branch that flashed the old
  cannot_edit_published message (its successor branch with
  cannot_edit_finalized stays). The old i18n key is left in lang/
  for now — orphan but harmless, can ressuscitate if a similar
  flash is added back.

app/Enums/Post/Action.php

@@ -6,7 +6,6 @@
 
 enum Action: string
 {
-    case AlreadyPublished = 'already_published';
     case Finalized = 'finalized';
     case Publishing = 'publishing';
     case Scheduled = 'scheduled';

app/Http/Controllers/Api/PostController.php

@@ -67,7 +67,7 @@ public function update(UpdatePostRequest $request, Post $post): PostResource|Jso
 
         $result = UpdatePost::execute($request->user()->currentWorkspace, $post, $request->validated());
 
-        if (in_array(data_get($result, 'action'), [PostAction::AlreadyPublished, PostAction::Finalized], true)) {
+        if (data_get($result, 'action') === PostAction::Finalized) {
             return response()->json(
                 ['message' => 'Cannot edit a published post.'],
                 Response::HTTP_UNPROCESSABLE_ENTITY

app/Http/Controllers/App/PostController.php

@@ -282,13 +282,6 @@ public function update(UpdatePostRequest $request, Post $post): RedirectResponse
 
         $action = data_get($result, 'action');
 
-        if ($action === PostAction::AlreadyPublished) {
-            session()->flash('flash.banner', __('posts.flash.cannot_edit_published'));
-            session()->flash('flash.bannerStyle', 'danger');
-
-            return back();
-        }
-
         if ($action === PostAction::Finalized) {
             session()->flash('flash.banner', __('posts.flash.cannot_edit_finalized'));
             session()->flash('flash.bannerStyle', 'danger');

app/Mcp/Tools/Post/PublishPostTool.php

@@ -47,7 +47,7 @@ public function handle(Request $request): Response|ResponseFactory
             'scheduled_at' => $scheduledAt,
         ]);
 
-        if (in_array(data_get($result, 'action'), [PostAction::AlreadyPublished, PostAction::Finalized], true)) {
+        if (data_get($result, 'action') === PostAction::Finalized) {
             return Response::error('Post is already published or in a terminal state.');
         }
 

app/Mcp/Tools/Post/UpdatePostTool.php

@@ -54,7 +54,7 @@ public function handle(Request $request): Response|ResponseFactory
 
         $result = UpdatePost::execute($workspace, $post, $payload);
 
-        if (in_array(data_get($result, 'action'), [PostAction::AlreadyPublished, PostAction::Finalized], true)) {
+        if (data_get($result, 'action') === PostAction::Finalized) {
             return Response::error('Cannot edit a published post.');
         }