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>

lib/Support/Search/SearchUiMetaProvider.php

@@ -5,7 +5,6 @@ namespace MintyPHP\Support\Search;
 class SearchUiMetaProvider
 {
     private const ICONS = [
-        'address-book' => 'bi-people',
         'users' => 'bi-person-badge',
         'tenants' => 'bi-buildings',
         'departments' => 'bi-diagram-3',
@@ -20,7 +19,6 @@ class SearchUiMetaProvider
     ];
 
     private const LIST_URL_KEYS = [
-        'address-book',
         'users',
         'tenants',
         'departments',
@@ -43,7 +41,6 @@ class SearchUiMetaProvider
         $encoded = urlencode($query);
 
         return match ($key) {
-            'address-book' => lurl('address-book') . '?search=' . $encoded,
             'users' => lurl('admin/users') . '?search=' . $encoded,
             'tenants' => lurl('admin/tenants') . '?search=' . $encoded,
             'departments' => lurl('admin/departments') . '?search=' . $encoded,