Finish the Macedonia stories and enrich image captions

Complete the three remaining Macedonia stories with sourced photos, so
both country sections are now fully illustrated.

Articles (EN/SI/MK each), placeholders replaced with real images:
- A Table Full of Macedonia (shared table, tavče gravče, ajvar,
  pastrmajlija).
- Music, Dance and the Moments That Bring Us Together (oro celebration,
  tapan and zurla, kopachkata, an MSOS event).
- History You Can Still Walk Through (Stobi, Heraclea Lyncestis, Kokino,
  Makedonium).
Each image is center-cropped to a uniform 3:2, downscaled, and given an
attribution caption with place, photographer where known, and source
link.

Captions:
- Replace bare one-word labels with a short descriptive phrase in all
  three languages, so a caption reads "Kokino, a prehistoric megalithic
  observatory" rather than just "Kokino". Applies across the food,
  culture, and heritage stories.
- Support an author-only credit with no external link, used for the
  photo from the MSOS archive.

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

mk/get-to-know-macedonia/index.html

@@ -238,10 +238,7 @@
                     <!-- Story: Македонија на полна трпеза -->
                     <article class="post-card" data-category="food">
                         <a href="a-table-full-of-macedonia/" class="post-link">
-                            <div class="post-image post-image-placeholder">
-                                <i class="fas fa-image" aria-hidden="true"></i>
-                                <span>Слика ќе се додаде</span>
-                            </div>
+                            <img src="../../images/macedonia-food-shared-table-hero.jpg" alt="A shared Macedonian table with salads, bread, beans, and other dishes" class="post-image">
                             <div class="post-content">
                                 <p class="post-meta">Тим на МСОС • Храна и вкусови</p>
                                 <h3 class="post-title">Македонија на полна трпеза</h3>
@@ -252,10 +249,7 @@
                     <!-- Story: Музика, оро и моментите што нè спојуваат -->
                     <article class="post-card" data-category="culture">
                         <a href="music-dance-and-the-moments-that-bring-us-together/" class="post-link">
-                            <div class="post-image post-image-placeholder">
-                                <i class="fas fa-image" aria-hidden="true"></i>
-                                <span>Слика ќе се додаде</span>
-                            </div>
+                            <img src="../../images/macedonia-culture-oro-celebration-hero.jpg" alt="Several generations joining the same oro at a Macedonian celebration" class="post-image">
                             <div class="post-content">
                                 <p class="post-meta">Тим на МСОС • Култура и традиции</p>
                                 <h3 class="post-title">Музика, оро и моментите што нè спојуваат</h3>
@@ -266,10 +260,7 @@
                     <!-- Story: Историја низ која сè уште можеме да чекориме -->
                     <article class="post-card" data-category="heritage">
                         <a href="history-you-can-still-walk-through/" class="post-link">
-                            <div class="post-image post-image-placeholder">
-                                <i class="fas fa-image" aria-hidden="true"></i>
-                                <span>Слика ќе се додаде</span>
-                            </div>
+                            <img src="../../images/macedonia-heritage-stobi-street-hero.jpg" alt="An ancient street and building remains at the archaeological site of Stobi" class="post-image">
                             <div class="post-content">
                                 <p class="post-meta">Тим на МСОС • Историја и наследство</p>
                                 <h3 class="post-title">Историја низ која сè уште можеме да чекориме</h3>