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/js/components/app-contrast-toggle.js

@@ -1,9 +1,10 @@
 /**
  * High-contrast mode toggle with localStorage persistence.
  */
-import { requireEl } from '../core/app-dom.js';
+import { warnOnce, resolveHost } from '../core/app-dom.js';
+import { createUiStorage } from '../core/app-ui-storage.js';
 
-const STORAGE_KEY = 'app-contrast';
+const STORAGE_KEY = 'contrast-mode';
 
 const setContrast = (contrast) => {
   const root = document.documentElement;
@@ -12,7 +13,9 @@ const setContrast = (contrast) => {
 
 const setIcon = (button, contrast) => {
   const icon = button.querySelector('i');
-  if (!icon) {return;}
+  if (!icon) {
+    return;
+  }
   icon.classList.remove('bi-circle-half', 'bi-highlights');
   icon.classList.add(contrast === 'high' ? 'bi-highlights' : 'bi-circle-half');
 };
@@ -21,30 +24,48 @@ const setPressedState = (button, contrast) => {
   button.setAttribute('aria-pressed', contrast === 'high' ? 'true' : 'false');
 };
 
-const initContrastToggle = () => {
-  const button = requireEl('[data-contrast-toggle]', { module: 'contrast-toggle' });
-  if (!button) {return;}
-  const root = document.documentElement;
-  const getCurrent = () => (root.dataset.contrast === 'high' ? 'high' : 'normal');
+export function initContrastToggle(root = document, options = {}) {
+  const selector = String(options.selector || '[data-contrast-toggle]').trim() || '[data-contrast-toggle]';
+  const storage = createUiStorage({
+    namespace: options.storageNamespace || 'app-ui',
+    version: options.storageVersion || 'v1',
+    scope: options.storageScope || 'contrast',
+  });
+  const scopedStorageKey = storage.buildKey('state', options.storageKey || STORAGE_KEY);
+
+  const host = resolveHost(root);
+  const button = host.matches?.(selector) ? host : host.querySelector(selector);
+  if (!(button instanceof HTMLElement)) {
+    warnOnce('UI_EL_MISSING', `Missing contrast toggle: ${selector}`, { module: 'contrast-toggle' });
+    return { destroy: () => {} };
+  }
+  if (button.dataset.contrastToggleBound === '1') {
+    return {
+      destroy: () => {
+        delete button.dataset.contrastToggleBound;
+      },
+    };
+  }
+  button.dataset.contrastToggleBound = '1';
+
+  const getCurrent = () => (document.documentElement.dataset.contrast === 'high' ? 'high' : 'normal');
   const current = getCurrent();
   setIcon(button, current);
   setPressedState(button, current);
 
-  button.addEventListener('click', () => {
+  const onClick = () => {
     const next = getCurrent() === 'high' ? 'normal' : 'high';
     setContrast(next);
     setIcon(button, next);
     setPressedState(button, next);
-    try {
-      window.localStorage.setItem(STORAGE_KEY, next);
-    } catch (e) {
-      // ignore storage errors
-    }
-  });
-};
+    storage.setItem(scopedStorageKey, next);
+  };
+  button.addEventListener('click', onClick);
 
-if (document.readyState === 'loading') {
-  document.addEventListener('DOMContentLoaded', initContrastToggle);
-} else {
-  initContrastToggle();
+  const destroy = () => {
+    button.removeEventListener('click', onClick);
+    delete button.dataset.contrastToggleBound;
+  };
+
+  return { destroy };
 }