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>

tests/Support/AppContainerIsolationTrait.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace MintyPHP\Tests\Support;
+
+use MintyPHP\App\AppContainer;
+
+trait AppContainerIsolationTrait
+{
+    private mixed $appContainerIsolationPrevious = null;
+    private bool $appContainerIsolationActive = false;
+
+    protected function pushAppContainer(AppContainer $container): void
+    {
+        if (!$this->appContainerIsolationActive) {
+            $this->appContainerIsolationPrevious = $GLOBALS['minty_app_container'] ?? null;
+            $this->appContainerIsolationActive = true;
+        }
+
+        $GLOBALS['minty_app_container'] = $container;
+    }
+
+    protected function restoreAppContainer(): void
+    {
+        if (!$this->appContainerIsolationActive) {
+            return;
+        }
+
+        if ($this->appContainerIsolationPrevious instanceof AppContainer) {
+            $GLOBALS['minty_app_container'] = $this->appContainerIsolationPrevious;
+        } else {
+            unset($GLOBALS['minty_app_container']);
+        }
+
+        $this->appContainerIsolationPrevious = null;
+        $this->appContainerIsolationActive = false;
+    }
+}