Redesign typography, add image rounding and smooth loading

- Global headings: drop ALL CAPS, use sentence case + weight 700
- Post cards: refined date (small/uppercase/muted), cleaner title hierarchy
- Single post: date metadata style, subtitle no-italic, body line-height 1.75
- Logo frame (#header .logo): border-radius 12px
- All images: border-radius 8px (posts), 6px (gallery)
- Smooth lazy-load: CSS fadeIn animation + JS fallback (image-fade.js)
- Cache-busting: typography CSS with Hugo timestamp query string
- Trip card: replace broken gallery link with direct Elbrus S3 image URL

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

themes/hugo-theme-massively/layouts/partials/htmlhead.html

@@ -48,7 +48,7 @@
 		<link rel="stylesheet" href="/css/footer-nav.css">
 		<link rel="stylesheet" href="/css/mobile-pagination.css">
 		<link rel="stylesheet" href="/css/back-to-top.css">
-		<link rel="stylesheet" href="/css/typography-improvements.css">
+		<link rel="stylesheet" href="/css/typography-improvements.css?v={{ now.Unix }}">
 		<link rel="stylesheet" href="/css/about-site.css">
 		<link rel="stylesheet" href="/css/copyright-visible.css">
 		<link rel="stylesheet" href="/css/nav-background.css">