fix(ui): collapse empty page header slots

packages/ui/components/PageHeader.wrn

@@ -576,6 +576,14 @@ current: true
       display: none;
     }
 
+    /* Compiled empty slots retain inert template markers, so :empty alone
+       cannot collapse their spacing in the rendered document. */
+    .wrn-page-header__meta:not(:has(> :not(template))),
+    .wrn-page-header__body:not(:has(> :not(template))),
+    .wrn-page-header__actions--slot-only:not(:has(> :not(template))) {
+      display: none;
+    }
+
     .wrn-page-header__meta {
       margin-top: 1.1rem;
     }

packages/ui/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@wrnexus/ui",
-  "version": "0.8.45",
+  "version": "0.8.46",
   "private": true,
   "type": "module",
   "main": "src/index.ts",

packages/ui/test/ui.test.ts

@@ -3349,6 +3349,13 @@ test("custom scrollbar styles the scrollbar and drops its fake output", async ()
   expect(style).toContain("18rem");
 });
 
+test("page header collapses compiled empty slot markers", () => {
+  const source = readFileSync(uiComponentPath("PageHeader"), "utf8");
+  expect(source).toContain(".wrn-page-header__meta:not(:has(> :not(template)))");
+  expect(source).toContain(".wrn-page-header__body:not(:has(> :not(template)))");
+  expect(source).toContain(".wrn-page-header__actions--slot-only:not(:has(> :not(template)))");
+});
+
 test("layout components ship their own styles instead of Tailwind utilities", () => {
   /*
    * These were built from utility classes and class: conditionals. That works