feat: right-click context menu and Delete key for chart drawings

Co-authored-by: Cursor <cursoragent@cursor.com>

manual_trading_hub/static/app.css

@@ -2928,6 +2928,72 @@ body.login-page {
   pointer-events: auto;
 }
 
+.market-draw-menu {
+  position: fixed;
+  z-index: 1200;
+  min-width: 168px;
+  padding: 4px 0;
+  border: 1px solid var(--border-soft);
+  border-radius: 8px;
+  background: var(--panel-bg, #1a1f2e);
+  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.45);
+}
+
+.market-draw-menu.hidden {
+  display: none;
+}
+
+.market-draw-menu-head {
+  padding: 6px 12px 4px;
+  font-size: 0.72rem;
+  font-weight: 600;
+  color: var(--muted);
+  text-transform: none;
+}
+
+.market-draw-menu-item {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  width: 100%;
+  padding: 7px 12px;
+  border: 0;
+  background: transparent;
+  color: var(--text);
+  font-size: 0.82rem;
+  font-family: var(--font);
+  text-align: left;
+  cursor: pointer;
+}
+
+.market-draw-menu-item:hover:not(:disabled) {
+  background: var(--inset-surface);
+}
+
+.market-draw-menu-item:disabled {
+  opacity: 0.45;
+  cursor: not-allowed;
+}
+
+.market-draw-menu-item.is-danger {
+  color: #f87171;
+}
+
+.market-draw-menu-sep {
+  border: 0;
+  border-top: 1px solid var(--border-soft);
+  margin: 4px 0;
+}
+
+.market-draw-menu-kbd {
+  margin-left: 12px;
+  padding: 1px 5px;
+  border-radius: 4px;
+  background: var(--inset-surface);
+  color: var(--muted);
+  font-size: 0.68rem;
+}
+
 .market-exchange-badge {
   position: absolute;
   left: 50%;