feat: introduce module system and extract address book as first module (MODULAR-MONOLITH-V1-001)

Add a module kernel (ModuleManifest, ModuleRegistry) that allows modules to
contribute routes, UI slots, search providers, layout context, session
lifecycle, and permissions. Modules are activated via config/modules.php or
APP_ENABLED_MODULES env variable. Conflicts (duplicate routes, permissions,
slot keys) cause a fail-fast with a clear error message.

Extract the address book from hardcoded Core integration points into the
first module (modules/addressbook/). The module provides:
- Aside icon-bar tab + People panel via UI slot system
- Global search resource via AddressBookSearchProvider
- Layout context data via AddressBookLayoutProvider
- Session lifecycle via AddressBookSessionProvider

Core cleanup removes address-book hardcodings from SearchSqlResourceProvider,
SearchUiMetaProvider, SearchItemMapperProvider, appBuildLayoutNavContext(),
and the aside templates. Permissions (ADDRESS_BOOK_VIEW) and business logic
(AddressBookService) remain in Core as they gate general user visibility.

Includes 38 new tests (894 total), PHPStan level 5 clean, and architecture
tests verifying zero hardcoded address-book references in search/templates.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

modules/addressbook/module.php

@@ -0,0 +1,57 @@
+<?php
+
+/**
+ * Address Book module manifest.
+ *
+ * Contributes the "People" aside tab/panel, global search section,
+ * layout context data, and session lifecycle.
+ *
+ * Permissions (address_book.view) remain in Core PermissionService because
+ * they gate general user-visibility in UserAuthorizationPolicy, not just
+ * address-book access. Asset groups remain in config/assets.php because the
+ * asset pipeline does not yet consume ModuleRegistry::getAssetGroups().
+ */
+return [
+    'id' => 'addressbook',
+    'version' => '1.0.0',
+    'enabled_by_default' => false,
+    'load_order' => 10,
+
+    'routes' => [],
+    'public_paths' => [],
+    'container_registrars' => [],
+
+    'ui_slots' => [
+        'aside.tab_panel' => [
+            [
+                'key' => 'people',
+                'label' => 'Address book',
+                'icon' => 'bi-people',
+                'href' => 'address-book',
+                'permission' => 'can_view_address_book',
+                'panel_template' => __DIR__ . '/templates/aside-people-panel.phtml',
+                'details_storage' => 'aside-people-tenant',
+                'details_open_active' => true,
+            ],
+        ],
+    ],
+
+    'search_resources' => [
+        \MintyPHP\Module\AddressBook\Providers\AddressBookSearchProvider::class,
+    ],
+
+    'asset_groups' => [],
+    'scheduler_jobs' => [],
+
+    'layout_context_providers' => [
+        \MintyPHP\Module\AddressBook\Providers\AddressBookLayoutProvider::class,
+    ],
+
+    'session_providers' => [
+        \MintyPHP\Module\AddressBook\Providers\AddressBookSessionProvider::class,
+    ],
+
+    'permissions' => [],
+
+    'migrations_path' => 'db/updates',
+];