fix(core): filter DSD template from client-navigation swap + update rubric

Client router: when swapping the layout shell's light-DOM children on
navigation, the new body from DOMParser contains a
<template shadowrootmode="open"> element (the SSR's Declarative Shadow
DOM). DOMParser doesn't process DSD, so it stays as a regular DOM element.
Inserting it as light DOM into a shell that already has a shadow root
caused a brief layout flash — the template element disrupted slot
projection for one frame.

Fix: filter out any <template> with a shadowrootmode attribute before
calling replaceChildren. The shadow root already exists from the
initial page load; the DSD template is stale and shouldn't be in the
light DOM.

Also: landing page rubric changed from "ai-first · open source framework"
to "webjs: ai-first framework" per user request.

Author: vivek7405

docs/app/page.ts

@@ -181,7 +181,7 @@ export default function LandingPage() {
     </style>
 
     <section class="hero">
-      <div class="rubric">● ai-first · open source framework</div>
+      <div class="rubric">● webjs: ai-first framework</div>
       <h1>The framework AI agents can read, write, and ship.</h1>
       <p>
         webjs is an AI-first, no-build, web-components-first framework inspired by Next.js.

packages/core/src/router-client.js

@@ -202,7 +202,14 @@ function swapBody(newBody) {
   ) {
     // Same layout shell — swap only the light-DOM children (page content).
     // Keep the shell element itself (and its shadow root with chrome).
-    const children = [...newShell.childNodes];
+    //
+    // Filter out <template shadowrootmode="open"> — that's the Declarative
+    // Shadow DOM from SSR. On client navigation the shadow root already
+    // exists; inserting the DSD template as light DOM would add a stale
+    // invisible element that can confuse slot projection and cause a flash.
+    const children = [...newShell.childNodes].filter(
+      (n) => !(n instanceof HTMLTemplateElement && /** @type any */ (n).getAttribute('shadowrootmode'))
+    );
     currentShell.replaceChildren(...children);
   } else {
     // Different structure — full swap.