branch-coexist: 3 neue decks 223015b-2026 / 223015c-2026 / dhbw-2026 daneben main

per user-request einen branch der main-content UND rewrite-content trägt — saubere separierung statt symlink/merge-conflict.

struktur:
- slides/<course>/ → main-content restored, eigene assets (kein new-demo-leak)
- slides/<course>-2026/ → rewrite-content, eigene assets (komplett kopiert + new demos)

Makefile: COURSES += 223015b-2026 223015c-2026 dhbw-2026 mit eigenen NAME/KAPITEL/DEPLOY/KLAUSUR-konfig. Klausur für b+c=1, dhbw=leer. Deploy-paths /hdm/223015b-2026 etc.

make build durchlaufen für alle 6 decks, 0 fehler.

dedup: 223015c+dhbw assets identisch in beiden ordnern (kein neu-demos auf b ergänzt). 223015b 86 → 120 files in -2026 (= +34 neue eroeffner/usb-c-drei-achsen/container-vs-codec/etc).

slides/223015c-2026/assets/demos/arp-lookup.html

@@ -0,0 +1,65 @@
+<!DOCTYPE html>
+<html lang="de">
+<head>
+  <meta charset="UTF-8">
+  <title>ARP</title>
+  <style>
+    html, body { margin: 0; padding: 0; background: #fff; font-family: system-ui, sans-serif; }
+    body { padding: 30px; display: inline-block; }
+    .row { display: flex; align-items: center; gap: 16px; margin-bottom: 20px; }
+    .actor {
+      background: #1a1a2e;
+      color: #fff;
+      padding: 10px 16px;
+      border-radius: 6px;
+      font-weight: 700;
+      min-width: 160px;
+      text-align: center;
+      font-size: 0.9rem;
+    }
+    .laptop { background: #1e40af; }
+    .router { background: #c2410c; }
+    .arrow-right, .arrow-left {
+      width: 0; height: 0;
+      border-top: 10px solid transparent;
+      border-bottom: 10px solid transparent;
+    }
+    .arrow-right { border-left: 14px solid #d63384; }
+    .arrow-left { border-right: 14px solid #15803d; }
+    .bubble {
+      padding: 10px 14px;
+      border-radius: 8px;
+      font-size: 0.95rem;
+      max-width: 460px;
+    }
+    .ask { background: #fce7f3; border: 2px solid #d63384; color: #7c2d12; }
+    .reply { background: #dcfce7; border: 2px solid #15803d; color: #14532d; }
+    .meta {
+      font-size: 0.7rem;
+      font-weight: 700;
+      text-transform: uppercase;
+      letter-spacing: 0.05em;
+      opacity: 0.7;
+      margin-bottom: 3px;
+    }
+  </style>
+</head>
+<body>
+  <div class="row">
+    <div class="actor laptop">Laptop</div>
+    <div class="arrow-right"></div>
+    <div class="bubble ask">
+      <div class="meta">Broadcast</div>
+      "Wer hat die IP 192.168.1.1? Sag mir deine MAC!"
+    </div>
+  </div>
+  <div class="row">
+    <div class="bubble reply">
+      <div class="meta">Antwort</div>
+      "Das bin ich! Meine MAC ist 11:22:33:44:55:66"
+    </div>
+    <div class="arrow-left"></div>
+    <div class="actor router">Router</div>
+  </div>
+</body>
+</html>