Review, publish, preview and undo changes through the API

Revisions now call publishing only what publishes: a project's status is
whether the work is active, and a service is published by its flag.

The fake identity server answers by token, so a test can sign in a second
person.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/Http/Controllers/Api/V1/RevisionController.php

@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Controllers\Api\V1;
+
+use App\Http\Controllers\Api\V1\Concerns\ResolvesContent;
+use App\Http\Controllers\Controller;
+use App\Http\Resources\RevisionResource;
+use App\Models\Revision;
+use App\Support\AdminContent;
+use Illuminate\Database\Eloquent\Relations\Relation;
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\AnonymousResourceCollection;
+use Illuminate\Validation\ValidationException;
+
+/**
+ * A record's history: who changed what and when, and undoing one change.
+ */
+class RevisionController extends Controller
+{
+    use ResolvesContent;
+
+    /**
+     * Newest first. Filter: event.
+     */
+    public function index(Request $request): AnonymousResourceCollection
+    {
+        $record = $this->record($request);
+
+        $this->authorize('view', $record);
+
+        $revisions = $record->revisions()
+            ->with('user')
+            ->when($request->filled('event'), fn ($q) => $q->where('event', $request->string('event')))
+            ->paginate(perPage: min($request->integer('per_page', 25), 100))
+            ->withQueryString();
+
+        return RevisionResource::collection($revisions);
+    }
+
+    /**
+     * Put back what one revision changed, as the panel's history does.
+     * Restoring is itself a change, so it lands in the history too — the way
+     * back is never lost.
+     */
+    public function restore(Request $request, Revision $revision): RevisionResource
+    {
+        $model = Relation::getMorphedModel($revision->revisionable_type) ?? $revision->revisionable_type;
+        $record = AdminContent::findOf($model, $revision->revisionable_id);
+
+        $this->authorize('update', $record);
+
+        $values = $revision->previousValues();
+
+        if ($values === []) {
+            throw ValidationException::withMessages(['revision' => [__('rules.revisions.nothing_to_restore')]]);
+        }
+
+        // Undoing a change can publish or unpublish, and that stays with whoever
+        // may publish.
+        $guarded = array_intersect(array_keys($values), AdminContent::publicationFields($record));
+
+        if ($guarded !== [] && $request->user()->cannot($record->getTable().'.publish')) {
+            throw ValidationException::withMessages(['revision' => [__('rules.publication.forbidden')]]);
+        }
+
+        // Only what the model lets a form write: a revision may mention
+        // bookkeeping columns, and those are not anybody's to put back.
+        $record->forceFill(array_intersect_key($values, array_flip($record->getFillable())))->save();
+
+        return RevisionResource::make($record->revisions()->with('user')->first());
+    }
+}