fix(security): no direct HTTP access to plugin PHP files (audit L2, cheap part)

Every file under src/ exits outside WordPress (defined('ABSPATH') ||
exit; after the use block, so a direct request no longer prints a fatal
error with the server path); divi-convert-fixture.php gets the WP_CLI
guard the other integration scripts have. A unit test keeps both true;
PSR1 side-effects warning excluded for the guard.

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

src/Integrations/Divi/Schema/AttrPathIndex.php

@@ -6,6 +6,8 @@ namespace LIT\MCP\Integrations\Divi\Schema;
 
 use LIT\MCP\Integrations\Divi\BlockTree\AttrMap;
 
+defined('ABSPATH') || exit;
+
 /**
  * Known attribute paths of one module, derived from Divi's module metadata (settings of
  * every attribute group, attrName references) and its default attributes (spec §5.4:

src/Integrations/Divi/Schema/DiviCatalogAbility.php

@@ -10,6 +10,8 @@ use LIT\MCP\Abilities\Errors;
 use LIT\MCP\Abilities\JsonMap;
 use WP_Error;
 
+defined('ABSPATH') || exit;
+
 /**
  * lit/divi-catalog: the modules of this Divi installation with their short-form fields;
  * with "module" the details of one module incl. all known attribute paths (spec §5.7).

src/Integrations/Divi/Schema/DiviModules.php

@@ -6,6 +6,8 @@ namespace LIT\MCP\Integrations\Divi\Schema;
 
 use ET\Builder\Packages\ModuleLibrary\ModuleRegistration;
 
+defined('ABSPATH') || exit;
+
 /**
  * Reads Divi's module metadata once per request (Divi 5 only). Not final so abilities can be
  * unit-tested with a mock.

src/Integrations/Divi/Schema/ModuleCatalog.php

@@ -4,6 +4,8 @@ declare(strict_types=1);
 
 namespace LIT\MCP\Integrations\Divi\Schema;
 
+defined('ABSPATH') || exit;
+
 /**
  * The modules this Divi installation knows (spec §5.7 lit-divi-catalog), built from
  * ModuleRegistration::get_all_core_modules_metadata() – always live, never a copy.

src/Integrations/Divi/Schema/ShortformMap.php

@@ -6,6 +6,8 @@ namespace LIT\MCP\Integrations\Divi\Schema;
 
 use LIT\MCP\Integrations\Divi\BlockTree\AttrMap;
 
+defined('ABSPATH') || exit;
+
 /**
  * Curated short form (spec §5.4) for the ~20 everyday modules: field => where Divi 5 keeps
  * the value. Paths come from Divi's conversion outlines (…/module-library/src/components/