style: add border-radius to rectangular elements

- Plot container: 0→8px
- Plot save button: 6→8px
- Import sections, share selects/textarea, API table, settings inputs: 8px

Co-Authored-By: Claude <noreply@anthropic.com>

app/src/main/assets/console.css

@@ -1424,7 +1424,7 @@ body {
     box-sizing: border-box;
     background: #FCFDFE;
     border: 2px solid #B0BEC5;
-    border-radius: 0;
+    border-radius: 8px;
     box-shadow: inset 0 0 0 1px rgba(0,0,0,0.03);
     overflow: hidden;
 }
@@ -1493,7 +1493,7 @@ body {
 .plot-save-btn {
     padding: 6px 14px;
     border: 1px solid var(--terminal-border);
-    border-radius: 6px;
+    border-radius: 8px;
     background: #FFFFFF;
     color: var(--primary-color);
     font-size: 12px;
@@ -1605,6 +1605,12 @@ body {
     line-height: 1.6;
 }
 
+/* ── 通用圆角 ──────────────────────────────────── */
+.import-section, .share-select, .share-textarea, .api-table,
+.setting-input, .setting-select, .setting-select:focus {
+    border-radius: 8px;
+}
+
 /* ── 全屏插件面板 ───────────────────────────────── */
 .fullscreen-panel {
     position: fixed;