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/Architecture/AppContainerIsolationContractTest.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace MintyPHP\Tests\Architecture;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Contract: Direct writes to $GLOBALS['minty_app_container'] are only allowed
+ * inside the dedicated AppContainerIsolationTrait.
+ */
+final class AppContainerIsolationContractTest extends TestCase
+{
+    use ProjectFileAssertionSupport;
+
+    public function testDirectAppContainerGlobalWritesAreRestrictedToIsolationTrait(): void
+    {
+        $violations = array_merge(
+            $this->findPatternMatchesInPhpFiles('tests', '/\\$GLOBALS\\[\'minty_app_container\'\\]\\s*=/'),
+            $this->findPatternMatchesInPhpFiles('tests', '/unset\\(\\$GLOBALS\\[\'minty_app_container\'\\]\\)/')
+        );
+
+        $allowed = [
+            'tests/Support/AppContainerIsolationTrait.php',
+        ];
+
+        $violations = array_values(array_filter(
+            array_unique($violations),
+            static fn (string $path): bool => !in_array($path, $allowed, true)
+        ));
+        sort($violations);
+
+        self::assertSame([], $violations, "Direct global app-container writes found outside isolation trait:\n" . implode("\n", $violations));
+    }
+}