Initial commit: Dostalgia — DOS game hub

- Go backend (single binary) with embedded Svelte frontend
- JSON-per-game storage (no database)
- .jsdos bundle creation on upload
- Dark phosphor-green theme (#33FF33)
- js-dos v8 emulator integration
- Sockdrive support for games >80MB
- IGDB placeholder for future artwork scraping
- Docker deployment ready

frontend/src/lib/Header.svelte

@@ -0,0 +1,65 @@
+<script>
+  import { push } from "./router.js";
+</script>
+
+<header class="header">
+  <div class="header-inner">
+    <a href="#/" class="logo" onclick={(e) => { e.preventDefault(); push("/"); }}>
+      <svg class="logo-icon" width="36" height="36" viewBox="0 0 36 36" fill="none">
+        <rect x="4" y="6" width="28" height="22" rx="2" fill="#33FF33" opacity="0.15"/>
+        <rect x="6" y="8" width="24" height="16" fill="#0A0A0A"/>
+        <rect x="8" y="10" width="20" height="10" fill="#33FF33" opacity="0.3"/>
+        <rect x="10" y="12" width="6" height="4" fill="#33FF33" opacity="0.6"/>
+        <rect x="18" y="12" width="6" height="4" fill="#33FF33" opacity="0.4"/>
+        <rect x="10" y="24" width="16" height="3" fill="#33FF33" opacity="0.2"/>
+        <rect x="12" y="29" width="12" height="2" fill="#33FF33" opacity="0.1"/>
+      </svg>
+      <span class="logo-text">DOSTALGIA</span>
+    </a>
+    <nav>
+      <button class="btn" onclick={() => push("/")}>Library</button>
+    </nav>
+  </div>
+</header>
+
+<style>
+  .header {
+    height: var(--header-height);
+    border-bottom: 1px solid var(--border);
+    background: var(--bg-elevated);
+    position: sticky;
+    top: 0;
+    z-index: 100;
+  }
+  .header-inner {
+    max-width: var(--max-width);
+    margin: 0 auto;
+    padding: 0 24px;
+    height: 100%;
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+  }
+  .logo {
+    display: flex;
+    align-items: center;
+    gap: 12px;
+    cursor: pointer;
+    text-decoration: none;
+  }
+  .logo-icon {
+    flex-shrink: 0;
+  }
+  .logo-text {
+    font-family: var(--font-mono);
+    font-size: 1.4rem;
+    font-weight: 700;
+    color: var(--phosphor);
+    letter-spacing: 0.15em;
+    animation: phosphor-pulse 3s ease-in-out infinite;
+  }
+  nav {
+    display: flex;
+    gap: 8px;
+  }
+</style>