fix: failed library and layout saves name the revision screen (audit L3)

A failed save of a library entry or Theme Builder layout now carries
restore_url when a revision exists; a partial write's hint points to the
WordPress revision screen and lit-divi-outline instead of
lit/revisions-list and lit/revision-restore, which answer not found for
these types. Pages keep the default hint.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

tests/Unit/Integrations/Divi/Pages/DiviWriterThemeBuilderTest.php

@@ -155,6 +155,23 @@ final class DiviWriterThemeBuilderTest extends TestCase
         self::assertSame([], $this->saved);
     }
 
+    /** Audit L3 on the failure path: a failed layout save names the WordPress revision screen. */
+    public function testAFailedSaveNamesTheRevisionScreen(): void
+    {
+        $this->failures = [WriteFailed::rolledBack(DiviSaver::REASON, new \RuntimeException('hook'), postId: 1062, revisionId: 811)];
+        $ability = new DiviInsertAbility($this->writer([ThemeBuilderFixtures::template()]));
+
+        try {
+            $ability->execute($this->insert($this->body, []));
+            self::fail('WriteFailed expected');
+        } catch (WriteFailed $e) {
+            $error = $e->toError();
+        }
+
+        self::assertSame('https://kunde.test/wp-admin/revision.php?revision=811', $error->get_error_data()['restore_url']);
+        self::assertStringNotContainsString('lit/revision-restore', $error->get_error_data()['hint']);
+    }
+
     /** Without a ThemeBuilderEdits (no Theme Builder wiring) a layout is never written. */
     public function testWithoutThemeBuilderEditsLayoutsAreNotWritten(): void
     {