feat: move footer privacy note behind PRIVACY overlay button

DeepDrftPublic.Client/Layout/DeepDrftFooter.razor.css

@@ -57,16 +57,26 @@
     color: var(--deepdrft-muted);
 }
 
-.deepdrft-footer-privacy {
+/* PRIVACY trigger — visually matches the footer <a> links (same font, size, casing, colour).
+   Reset all button chrome so it reads as a link, not a button element. */
+.deepdrft-footer-privacy-btn {
     font-family: var(--deepdrft-font-mono);
-    font-size: 0.55rem;
-    letter-spacing: 0.08em;
+    font-size: 0.62rem;
+    letter-spacing: 0.18em;
+    text-transform: uppercase;
     color: var(--deepdrft-muted);
-    opacity: 0.7;
+    text-decoration: none;
+    transition: color 0.2s;
+    background: none;
+    border: none;
+    padding: 0;
     margin: 0;
-    line-height: 1.6;
+    cursor: pointer;
+    line-height: inherit;
 }
 
+.deepdrft-footer-privacy-btn:hover { color: var(--deepdrft-navy); }
+
 @media (max-width: 440px) {
     .deepdrft-footer {
         padding: 1.5rem;