feat: 币种输入旁实时显示交易所现价

Shared SymbolLivePrice polls /api/order_defaults on input with debounce; wired to trade, key monitor, trend, and key focus forms.

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

lib/common/static/instance_theme.css

@@ -1611,3 +1611,51 @@ html[data-theme="light"] .trade-policy-dir-lock {
   border-color: #9ed4b8;
 }
 
+/* ── 币种输入实时现价 ── */
+.symbol-live-price {
+  display: inline-flex;
+  align-items: center;
+  padding: 4px 10px;
+  border-radius: 8px;
+  font-size: 0.8rem;
+  font-weight: 600;
+  color: #8fc8ff;
+  background: rgba(31, 58, 90, 0.35);
+  border: 1px solid rgba(143, 200, 255, 0.22);
+  white-space: nowrap;
+  line-height: 1.35;
+}
+
+.symbol-live-price--ok {
+  color: #4cd97f;
+  border-color: rgba(76, 217, 127, 0.35);
+  background: rgba(76, 217, 127, 0.08);
+}
+
+.symbol-live-price--loading {
+  opacity: 0.75;
+}
+
+.symbol-live-price--err {
+  color: #e8a090;
+  border-color: rgba(232, 160, 144, 0.35);
+}
+
+.symbol-live-price-note {
+  font-size: 0.72rem;
+  color: #8892b0;
+  white-space: nowrap;
+}
+
+html[data-theme="light"] .symbol-live-price {
+  color: #1a4a7a;
+  background: #eef4fb;
+  border-color: #b8cfe8;
+}
+
+html[data-theme="light"] .symbol-live-price--ok {
+  color: #087a50;
+  background: #e8f8f0;
+  border-color: #9ed4b8;
+}
+