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>

lib/App/Module/ModuleRuntimePageBuilder.php

@@ -0,0 +1,135 @@
+<?php
+
+namespace MintyPHP\App\Module;
+
+use FilesystemIterator;
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
+use RuntimeException;
+
+/**
+ * Builds a runtime PageRoot by symlinking core and enabled module pages.
+ */
+final class ModuleRuntimePageBuilder
+{
+    /**
+     * @param array<string, ModuleManifest> $modules
+     * @return array{core_entries: int, module_entries: int}
+     */
+    public function build(string $runtimeDir, string $corePagesDir, array $modules): array
+    {
+        $corePages = realpath($corePagesDir);
+        if ($corePages === false) {
+            throw new RuntimeException('Core pages/ directory not found.');
+        }
+
+        if (count($modules) === 0) {
+            $this->pointRuntimeToCore($runtimeDir, $corePages);
+            return ['core_entries' => 0, 'module_entries' => 0];
+        }
+
+        if (is_link($runtimeDir)) {
+            unlink($runtimeDir);
+        }
+        if (!is_dir($runtimeDir) && !mkdir($runtimeDir, 0775, true) && !is_dir($runtimeDir)) {
+            throw new RuntimeException('Cannot create runtime pages directory: ' . $runtimeDir);
+        }
+
+        $this->removeDirectoryContents($runtimeDir);
+
+        $coreEntries = scandir($corePages);
+        if ($coreEntries === false) {
+            throw new RuntimeException('Cannot scan core pages directory.');
+        }
+
+        $coreCount = 0;
+        foreach ($coreEntries as $entry) {
+            if ($entry === '.' || $entry === '..') {
+                continue;
+            }
+            $source = $corePages . '/' . $entry;
+            $target = $runtimeDir . '/' . $entry;
+            if (!@symlink($source, $target)) {
+                throw new RuntimeException("Failed to create symlink: {$target} → {$source}");
+            }
+            $coreCount++;
+        }
+
+        $modulePageCount = 0;
+        foreach ($modules as $manifest) {
+            $modulePagesDir = $manifest->basePath . '/pages';
+            if (!is_dir($modulePagesDir)) {
+                continue;
+            }
+            $entries = scandir($modulePagesDir);
+            if ($entries === false) {
+                continue;
+            }
+            foreach ($entries as $entry) {
+                if ($entry === '.' || $entry === '..') {
+                    continue;
+                }
+                $source = $modulePagesDir . '/' . $entry;
+                $target = $runtimeDir . '/' . $entry;
+                if (file_exists($target) || is_link($target)) {
+                    throw new RuntimeException(
+                        "Page path collision: '{$entry}' from module '{$manifest->id}' conflicts with existing page."
+                    );
+                }
+                if (!@symlink($source, $target)) {
+                    throw new RuntimeException("Failed to create symlink: {$target} → {$source}");
+                }
+                $modulePageCount++;
+            }
+        }
+
+        return [
+            'core_entries' => $coreCount,
+            'module_entries' => $modulePageCount,
+        ];
+    }
+
+    public function pointRuntimeToCore(string $runtimeDir, string $corePages): void
+    {
+        if (is_dir($runtimeDir) && !is_link($runtimeDir)) {
+            $this->removeDirectoryContents($runtimeDir);
+            rmdir($runtimeDir);
+        }
+        if (is_link($runtimeDir)) {
+            unlink($runtimeDir);
+        }
+        if (!@symlink($corePages, $runtimeDir)) {
+            throw new RuntimeException("Failed to create symlink: {$runtimeDir} → {$corePages}");
+        }
+    }
+
+    private function removeDirectoryContents(string $dir): void
+    {
+        $entries = scandir($dir);
+        if ($entries === false) {
+            return;
+        }
+        foreach ($entries as $entry) {
+            if ($entry === '.' || $entry === '..') {
+                continue;
+            }
+            $path = $dir . '/' . $entry;
+            if (is_link($path)) {
+                unlink($path);
+                continue;
+            }
+            if (is_dir($path)) {
+                $items = new RecursiveIteratorIterator(
+                    new RecursiveDirectoryIterator($path, FilesystemIterator::SKIP_DOTS),
+                    RecursiveIteratorIterator::CHILD_FIRST
+                );
+                foreach ($items as $item) {
+                    $item->isDir() ? rmdir($item->getPathname()) : unlink($item->getPathname());
+                }
+                rmdir($path);
+                continue;
+            }
+            unlink($path);
+        }
+    }
+}