feat: module architecture improvements — session keys, dependency graph, event dispatcher, deactivation hooks

Six targeted improvements to the modular monolith platform:

1. Fix AddressBook session key prefix to follow module.<id>.* convention
2. Move ADDRESS_BOOK_VIEW permission constant from core PermissionService into module
3. Add declarative JSON schema for module manifests (.agents/contracts/)
4. Add `requires` field with missing-dependency and circular-dependency detection
5. Add lightweight fire-and-forget event dispatcher (user.created/deleted/login/logout)
6. Add module deactivation hook interface and CLI script (bin/module-deactivate.php)

Includes 15 new architecture/unit tests covering all new functionality.

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

modules/addressbook/lib/Module/AddressBook/Providers/AddressBookLayoutProvider.php

@@ -31,8 +31,8 @@ final class AddressBookLayoutProvider implements LayoutContextProvider
                 'activeDepartments' => appNormalizePositiveIntList($query['departments'] ?? ''),
                 'activeRoles' => appNormalizePositiveIntList($query['roles'] ?? ''),
                 'activeCustomFilters' => self::normalizeCustomFilterQuery($query),
-                'peopleGroups' => is_array($session['available_departments_by_tenant'] ?? null)
-                    ? $session['available_departments_by_tenant']
+                'peopleGroups' => is_array($session['module.addressbook.departments_by_tenant'] ?? null)
+                    ? $session['module.addressbook.departments_by_tenant']
                     : [],
             ],
         ];