facelift polish: native cross-document view transitions + og regen

@view-transition navigation:auto (pure CSS crossfade, 180ms; Firefox ignores, reduced-motion
disables) - zero JS, zero CSP surface. og.png regenerated from the electric-identity script.
Favicon already carries the identity (gradient jw chip + caret) - deliberately unchanged.

src/styles/global.css

@@ -494,3 +494,16 @@ html.js [data-reveal] .chip {
     display: none;
   }
 }
+
+/* ---- Cross-document view transitions (facelift polish) --------------------
+   Native CSS only: Chromium/Safari get a soft crossfade between pages; Firefox
+   ignores. Zero JS, zero CSP surface, and reduced-motion turns it off. */
+@media (prefers-reduced-motion: no-preference) {
+  @view-transition {
+    navigation: auto;
+  }
+  ::view-transition-old(root),
+  ::view-transition-new(root) {
+    animation-duration: 180ms;
+  }
+}