feat(ui): 移除站点Y轴波浪偏移并简化线路绘制

移除波浪偏移计算逻辑，将贝塞尔曲线线路改为直线段连接，简化了绘图代码。

web/ticket-order.js

@@ -190,13 +190,10 @@
           }
 
           stationYByCanonical = {};
-          let stationIndex = 0;
           for (const c of Object.keys(primaryLineByStation)) {
               const li = primaryLineByStation[c];
               if (li == null) continue;
-              const waveOffset = (stationIndex % 2 === 0) ? -12 : 12;
-              stationYByCanonical[c] = baseY + li * lineGapY + waveOffset;
-              stationIndex++;
+              stationYByCanonical[c] = baseY + li * lineGapY;
           }
 
           const allStations = Object.keys(primaryLineByStation);
@@ -232,10 +229,7 @@
                   
                   let d = `M ${pts[0].x} ${pts[0].y}`;
                   for (let i = 1; i < pts.length; i++) {
-                      const prev = pts[i-1];
-                      const curr = pts[i];
-                      const midX = (prev.x + curr.x) / 2;
-                      d += ` C ${midX} ${prev.y}, ${midX} ${curr.y}, ${curr.x} ${curr.y}`;
+                      d += ` L ${pts[i].x} ${pts[i].y}`;
                   }
                   svgContent += `<path d="${d}" fill="none" stroke="${li.color}" stroke-width="8" stroke-linecap="round" stroke-linejoin="round" />`;
               }