Add dedicated edition pages (server, workstation, cloud)

- Add /server, /workstation, /cloud routes with per-page SEO titles
- Extract shared nav, footer, and waitlist form into partials
- Nav links to edition pages with active-state highlighting; swap About/Security order
- Waitlist form pre-checks the current edition and adds a Cloud option
- Add page-hero variant, edition switcher, and active-nav styles
- Responsive fixes: nav wraps at 540px, waitlist checkboxes wrap on narrow screens

templates/partials/nav.html

@@ -0,0 +1,47 @@
+{{define "nav"}}
+<a href="#main" class="skip-link">Skip to main content</a>
+
+<header class="nav">
+    <div class="nav-inner">
+        <a href="/" class="logo">
+            <svg class="logo-icon" width="28" height="28" viewBox="0 0 32 32" fill="none">
+                <rect width="32" height="32" fill="#0b0c0e"/>
+                <path d="M5 27L16 5L27 27" fill="none" stroke="#f59e0b" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"/>
+                <path d="M9 20H23" fill="none" stroke="#f59e0b" stroke-width="2.5" stroke-linecap="round"/>
+            </svg>
+            <span>Arcline Project</span>
+        </a>
+        <nav>
+            <a href="/server"{{if eq .Active "server"}} class="nav-active" aria-current="page"{{end}}>Server</a>
+            <a href="/workstation"{{if eq .Active "workstation"}} class="nav-active" aria-current="page"{{end}}>Workstation</a>
+            <a href="/cloud"{{if eq .Active "cloud"}} class="nav-active" aria-current="page"{{end}}>Cloud</a>
+            <a href="/#about">About</a>
+            <a href="/#security">Security</a>
+            <a href="/#contribute">Contribute</a>
+            <button
+                type="button"
+                data-theme-toggle
+                class="theme-toggle"
+                aria-label="Toggle theme"
+                title="Toggle light / dark mode"
+            >
+                <svg class="theme-icon theme-icon-light" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+                    <circle cx="12" cy="12" r="5"/>
+                    <line x1="12" y1="1" x2="12" y2="3"/>
+                    <line x1="12" y1="21" x2="12" y2="23"/>
+                    <line x1="4.22" y1="4.22" x2="5.64" y2="5.64"/>
+                    <line x1="18.36" y1="18.36" x2="19.78" y2="19.78"/>
+                    <line x1="1" y1="12" x2="3" y2="12"/>
+                    <line x1="21" y1="12" x2="23" y2="12"/>
+                    <line x1="4.22" y1="19.78" x2="5.64" y2="18.36"/>
+                    <line x1="18.36" y1="5.64" x2="19.78" y2="4.22"/>
+                </svg>
+                <svg class="theme-icon theme-icon-dark" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+                    <path d="M21 12.79A9 9 0 1111.21 3 7 7 0 0021 12.79z"/>
+                </svg>
+            </button>
+            <a href="#get-started" class="nav-cta">Get Started</a>
+        </nav>
+    </div>
+</header>
+{{end}}