feat(header): stack ANL wordmark in three lines and show desktop nav from 1000px

- Replace the "ANL" + "AI Agent Networking LAB" pair with a stacked
  "AI Agent / Networking / Laboratory" wordmark in Geist semibold; the
  cobalt initials spell out ANL.
- Add a header-only `nav` screen (1000px) so the inline desktop nav
  replaces the mobile menu earlier than the shared `desktop` (1240px)
  breakpoint, with compact tracking/padding between 1000px and 1239px.
  The masthead strip and project page layout still use `desktop`.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RcexqbEX5CnaLog2xNFQN7

refer_landing_page/tailwind.config.ts

@@ -29,6 +29,8 @@ const config: Config = {
   theme: {
     extend: {
       screens: {
+        // Header swaps the mobile menu for the inline nav (compact spacing until `desktop`).
+        nav: "1000px",
         desktop: "1240px",
       },
       colors: {