feat(design): single-page consolidation, drop typeface picker

Merge projects + homelab + timeline into one scrollable page.
Remove typeface picker (sans/serif/mono), keep theme toggle.
Nav simplified to name + toggle. Hero gains anchor links for
in-page navigation (#projects, #journey, #homelab). Old pages
become meta-refresh redirects. Timeline redesigned as two-column
grid layout — date left, content right — cutting vertical space
~50%. Focus states added for keyboard nav. Tags dropped from
timeline entries.

src/components/Hero.astro

@@ -42,4 +42,10 @@
       Email
     </a>
   </nav>
+
+  <nav class="flex flex-wrap items-center gap-x-2ch gap-y-half-lh text-[var(--color-text-dim)] mt-half-lh">
+    <a href="#projects" class="underline hover:text-[var(--color-text)]">Projects</a>
+    <a href="#journey" class="underline hover:text-[var(--color-text)]">Journey</a>
+    <a href="#homelab" class="underline hover:text-[var(--color-text)]">Homelab</a>
+  </nav>
 </section>