fix: name the WordPress revision screen for library and layout revisions (audit L3)

lit/revision-restore takes only content types, so a write to a library entry
or a Theme Builder layout now answers with restore_url (wp-admin
revision.php for its revision_id), also per page in lit/divi-replace-text.
The guides and readme no longer present lit/revision-restore as the way back
for these types.

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/DiviInsertAbilityTest.php

@@ -23,6 +23,7 @@ final class DiviInsertAbilityTest extends DiviWriteAbilityTestCase
         self::assertSame(Rev::of($this->saved[0]), $result['tree_rev']);
         self::assertSame(Rev::ofPost($this->post), $result['rev']);
         self::assertSame(811, $result['revision_id']);
+        self::assertArrayNotHasKey('restore_url', $result, 'pages: lit/revision-restore');
         self::assertSame(4711, $result['log_id']);
         self::assertStringStartsWith('s0 section "Hero"', (string) $result['outline']);
         self::assertSame('https://kunde.test/?page_id=7&et_fb=1', $result['edit_url']);