feat(settings): gear dropdown opening focused settings sections

The purse gear now opens a dropdown (Audio / Discord / Chat / Altre / Filtro
Parole). Audio/Chat/Altre open UserSettingsView focused on that section
(reusing the existing volume + preference controls) with a Back button; Discord
and Filtro Parole are placeholders for now.

src/css/purse/PurseView.css

@@ -230,6 +230,45 @@
     object-fit: contain;
 }
 
+/* ---- Settings dropdown (gear menu) ---- */
+.nitro-purse-menu {
+    width: 100%;
+    max-width: 200px;
+    margin-top: 4px;
+    margin-left: auto;
+    display: flex;
+    flex-direction: column;
+    overflow: hidden;
+    border: 2px solid #41403c;
+    border-radius: 8px;
+    background: rgba(10, 10, 12, 0.92);
+    box-shadow: 0 8px 18px rgba(0, 0, 0, 0.3);
+    pointer-events: all;
+}
+
+.nitro-purse-menu__item {
+    padding: 6px 10px;
+    text-align: left;
+    font-size: 0.78rem;
+    font-weight: 500;
+    color: rgba(255, 255, 255, 0.9);
+    background: transparent;
+    border: 0;
+    cursor: pointer;
+    transition: background 0.12s ease;
+}
+
+.nitro-purse-menu__item:hover {
+    background: rgba(255, 255, 255, 0.08);
+}
+
+.nitro-purse-menu__item--disabled,
+.nitro-purse-menu__item--disabled:hover {
+    color: rgba(255, 255, 255, 0.35);
+    background: transparent;
+    cursor: default;
+}
+
 @media (max-width: 640px) {
     .nitro-purse {
         max-width: 100%;