fix: stop guessing a kind for composite Divi attribute paths

Review fix round 1 on the lit/divi-catalog task:
- AttrPathIndex::collectKinds() no longer records a kind from a
  component.type === "group" node (a composite of several sub-kinds,
  e.g. button.innerContent = text + link + target), and kinds() now
  drops any attrName with more than one distinct candidate kind
  instead of last-write-wins (e.g. imageIcon.innerContent had onoff +
  icon + image sub-fields sharing one attrName). Both previously
  produced a wrong-but-present kind, which is more dangerous for 2b's
  sanitization routing than "unknown". Verified against the committed
  blurb/button/fullwidth-header fixture entries and live against the
  full 100-module catalog.
- AttrPathIndex::fromDefaults() now builds on AttrMap::flatten()
  instead of a parallel walker.
- ModuleCatalog::shortName() replaces the duplicated
  substr($name, strlen('divi/')) in DiviCatalogAbility.

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

src/Integrations/Divi/Schema/DiviCatalogAbility.php

@@ -119,7 +119,8 @@ final class DiviCatalogAbility implements Ability
         if (! is_string($input['module'] ?? null) || $input['module'] === '') {
             $modules = [];
             foreach ($catalog->summary() as $module) {
-                $modules[] = $module + ['shortform' => ShortformMap::has(substr($module['name'], strlen('divi/')))];
+                $shortName = ModuleCatalog::shortName($module['name']);
+                $modules[] = $module + ['shortform' => ShortformMap::has($shortName)];
             }
 
             return ['modules' => $modules, 'notes' => $notes];
@@ -133,7 +134,7 @@ final class DiviCatalogAbility implements Ability
             );
         }
 
-        $short = substr($name, strlen('divi/'));
+        $short = ModuleCatalog::shortName($name);
         $item = ShortformMap::childType($short);
 
         return [