⚙️ Prepare v3 release: module path, version window, 3.0.0

Bump the Hugo module path to /v3, adopt a rolling latest-4 Hugo
version window (bot keeps it sliding), document new opt-in params,
and set package version to 3.0.0.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/pages.yml

@@ -30,7 +30,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     env:
-      HUGO_VERSION: 0.102.3
+      HUGO_VERSION: 0.165.0
     steps:
       - name: Install Hugo CLI
         run: |