refactor: DiviWriteAbility base and shared DiviErrors (H4)

The five Divi write tools extend DiviWriteAbility (final permission and
execute, change() per tool, shared output schema). DiviErrors holds the
unknown-node, position and compose-error mapping; DiviContentComposer uses
the same mapping (ledger T9). ToolNamingTest skips abstract classes.

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

src/Integrations/Divi/Pages/DiviDeleteAbility.php

@@ -4,9 +4,7 @@ declare(strict_types=1);
 
 namespace LIT\MCP\Integrations\Divi\Pages;
 
-use LIT\MCP\Abilities\Ability;
 use LIT\MCP\Abilities\Errors;
-use LIT\MCP\Abilities\ToolResult;
 use LIT\MCP\Integrations\Divi\BlockTree\Block;
 use LIT\MCP\Integrations\Divi\BlockTree\NodeSummary;
 use WP_Error;
@@ -17,12 +15,8 @@ use WP_Error;
  * nodes inside another node that is deleted anyway do not count twice. The revision in the
  * result allows undoing it (lit/revision-restore).
  */
-final class DiviDeleteAbility implements Ability
+final class DiviDeleteAbility extends DiviWriteAbility
 {
-    public function __construct(private DiviWriter $writer)
-    {
-    }
-
     public function name(): string
     {
         return 'lit/divi-delete';
@@ -59,41 +53,19 @@ final class DiviDeleteAbility implements Ability
         ];
     }
 
-    public function outputSchema(): ?array
-    {
-        return ToolResult::schema(['tree_rev' => ['type' => 'string']], ['tree_rev']);
-    }
-
     public function annotations(): array
     {
         return ['readonly' => false, 'destructive' => true, 'idempotent' => false];
     }
 
-    public function isDirect(): bool
+    protected function change(DiviPage $page, array $input, DiviComposition $composition): DiviChange|WP_Error
     {
-        return true;
-    }
-
-    public function permission(array $input): bool|WP_Error
-    {
-        $page = $this->writer->page($input);
-
-        return $page instanceof WP_Error ? $page : true;
-    }
-
-    public function execute(array $input): mixed
-    {
-        $page = $this->writer->page($input);
-        if ($page instanceof WP_Error) {
-            return $page;
-        }
-
         /** @var array<string, Block> $nodes */
         $nodes = [];
         foreach (is_array($input['ids'] ?? null) ? $input['ids'] : [] as $id) {
             $node = is_string($id) ? $page->index->find($id) : null;
             if ($node === null) {
-                return DiviPageLoader::unknownNode((string) $id, $page->post);
+                return DiviErrors::unknownNode((string) $id, $page->post);
             }
             $nodes[$id] = $node;
         }
@@ -115,14 +87,14 @@ final class DiviDeleteAbility implements Ability
             );
         }
 
-        $editor = $this->writer->composition($page)->editor();
+        $editor = $composition->editor();
         $change = new DiviChange(sprintf('%d Divi-Knoten gelöscht', count($nodes)));
         foreach ($nodes as $id => $node) {
             $change->removed((string) $id, $node);
             $editor->remove($page->index, $node);
         }
 
-        return $this->writer->save($this->name(), $page, $change, $input);
+        return $change;
     }
 
     /** @param array<string, Block> $nodes */