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;
-    }
-  }
 }

web/css/components/app-dialog.css

@@ -0,0 +1,75 @@
+/**
+ * app-dialog.css
+ * Base dialog styles shared by all dialog variants (confirm, bookmark, session-warning).
+ * Handles footer layout, button sizing, header close button, and mobile fallback.
+ * Variant-specific styles live in their own component files (app-confirm-dialog.css, etc.).
+ */
+@layer components {
+  /* ── Footer layout ───────────────────────────────────────────────────── */
+  dialog > article > footer,
+  dialog > article form > footer {
+    display: flex;
+    justify-content: flex-end;
+    gap: 0.5rem;
+  }
+
+  /* ── Footer buttons: auto-width, no margin ───────────────────────────── */
+  dialog > article > footer [role="button"],
+  dialog > article > footer button,
+  dialog > article form > footer [role="button"],
+  dialog > article form > footer button {
+    width: auto;
+    margin: 0;
+  }
+
+  /* ── Header: title flush, close button positioned ────────────────────── */
+  dialog > article > header > * {
+    margin-bottom: 0;
+  }
+
+  dialog > article > header .close,
+  dialog > article > header :is(a, button)[rel="prev"] {
+    margin: 0;
+    margin-left: var(--app-spacing);
+    padding: 0;
+    float: right;
+  }
+
+  /* ── Close icon ──────────────────────────────────────────────────────── */
+  dialog > article .close,
+  dialog > article :is(a, button)[rel="prev"] {
+    display: block;
+    width: 1rem;
+    height: 1rem;
+    margin-top: calc(var(--app-spacing) * -1);
+    margin-bottom: var(--app-spacing);
+    margin-left: auto;
+    border: none;
+    background-image: var(--app-icon-close);
+    background-position: center;
+    background-size: auto 1rem;
+    background-repeat: no-repeat;
+    background-color: transparent;
+    opacity: 0.5;
+    transition: opacity var(--app-transition);
+  }
+
+  dialog > article .close:is([aria-current]:not([aria-current="false"]), :hover, :active, :focus),
+  dialog > article :is(a, button)[rel="prev"]:is([aria-current]:not([aria-current="false"]), :hover, :active, :focus) {
+    opacity: 1;
+  }
+
+  /* ── Mobile: stack buttons vertically ────────────────────────────────── */
+  @media (max-width: 576px) {
+    dialog > article > footer,
+    dialog > article form > footer {
+      flex-direction: column-reverse;
+      align-items: stretch;
+    }
+
+    dialog > article > footer button,
+    dialog > article form > footer button {
+      width: 100%;
+    }
+  }
+}