health: fix broken pages, add image dimensions, a11y & SEO wins

Site-wide health pass (excludes in-progress blog work). Verified with a
local server + headless browser: Timeline, homepage and gallery pages load
with zero console errors and no layout distortion.

Render bugs
- Timeline page (en/mk/si): fix ../../../ paths that overshot the site root,
  so the main stylesheet and hero image load again.
- Meet Student Slovenia 2023 (en/mk/si): remove a <figure> referencing
  event3-photo-11.png, an image that was never uploaded (broken image).

Performance
- Add intrinsic width/height to 1039 raster <img> tags to prevent layout
  shift (CLS); 450 SVGs correctly skipped. Add a global
  `img { max-width:100%; height:auto }` safety net so aspect ratio is
  preserved and images never overflow.
- Preload the homepage hero (LCP) image on en/mk/si.
- Load Font Awesome non-blocking (media=print/onload swap) with a <noscript>
  fallback, on 225 pages.

Accessibility
- Add aria-label to 57 unlabeled newsletter email inputs.
- Add an sr-only <h1> to the three "My Route" pages (had no h1).
- Add an .sr-only utility class.

SEO
- Add meta descriptions to legal/msos-hub/support pages (en/mk/si).

Note: MK/SI meta descriptions are machine-drafted and should be proofread
by a native speaker before considering them final.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

css/base/_base.css

@@ -2,6 +2,28 @@
    Base Styles
    ========================================================================== */
 
+/* Screen-reader-only utility: visually hidden but announced by assistive tech.
+   Used for accessible headings that don't need to be shown visually. */
+.sr-only {
+    position: absolute !important;
+    width: 1px; height: 1px;
+    padding: 0; margin: -1px;
+    overflow: hidden;
+    clip: rect(0, 0, 0, 0);
+    white-space: nowrap;
+    border: 0;
+}
+
+/* Responsive-image safety net. Pairs with the width/height attributes now on
+   every <img>: keeps images from overflowing their container and preserves
+   aspect ratio (prevents distortion) for any image without a specific size
+   rule. Component rules with their own height (.news-card img, .eg-thumb img,
+   object-fit covers, logos, etc.) are more specific and still win. */
+img {
+    max-width: 100%;
+    height: auto;
+}
+
 /**
  * 1. Temeljni stili za celotno stran (box-sizing, osnovna pisava, barve).
  * 2. Definicija glavnega `.container` razreda za omejitev širine vsebine.