feat: extend module platform with UI slots, runtime components, CLI tooling and {{userId}} search support

Completes the generic module platform that enables modules to contribute
UI elements, runtime JS components, and search resources without any
core hardcoding.

New generic UI slot types:
- topbar.right_item: module-contributed topbar buttons
- layout.body_end_template: module-contributed dialog/overlay templates
- layout.head_style: module-contributed global CSS
- runtime.component: declarative JS component registration with phase ordering

New infrastructure:
- ModuleAutoloader: PSR-4 autoloading for module-local PHP classes
- ModuleRuntimePageBuilder: symlinks module pages into runtime directory
- ModuleRuntimeAssetPublisher: publishes module CSS/JS to web/modules/
- ModulePermissionSynchronizer: syncs module permissions to DB
- CLI scripts: module-runtime-sync, module-build, module-migrate,
  module-permissions-sync, module-assets-sync
- {{userId}} placeholder in SearchDataService for user-scoped search queries
- Component runtime with phased initialization (early/default/late)
- AppContainer.protectExistingBindings() to prevent module→core overwrites
- Architecture tests: ModuleStructureContractTest, CoreTemplateIsolationTest,
  FrontendComponentRuntimeContractTest, AppContainerIsolationContractTest

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

web/css/components/app-confirm-dialog.css

@@ -32,16 +32,9 @@
   }
 
   dialog[data-app-confirm-dialog] footer {
-    display: flex;
-    justify-content: flex-end;
-    gap: 0.5rem;
     padding: 10px;
   }
 
-  dialog[data-app-confirm-dialog] footer button {
-    margin: 0;
-  }
-
   dialog[data-app-confirm-dialog][data-confirm-variant="danger"] > article {
     border-top: 3px solid var(--app-del-color, #b42318);
   }
@@ -49,11 +42,4 @@
   dialog[data-app-confirm-dialog][data-confirm-variant="warning"] > article {
     border-top: 3px solid var(--app-warning-color, #b54708);
   }
-
-  @media (max-width: 576px) {
-    dialog[data-app-confirm-dialog] footer {
-      flex-direction: column-reverse;
-      align-items: stretch;
-    }
-  }
 }