路口信号灯颜色控制：默认固定南北绿灯东西红灯，支持参数切换

  1. 路口信号灯状态可控
    - _makeIntersectionConfig、apiGetIntersectionData、apiGetSpecialTaskMonitorData 新增 fixedNsGreen 参数
    - 默认 fixedNsGreen = true：南北（上下）固定绿色通行，东西（左右）固定红色停止
    - 传入 fixedNsGreen = false：恢复基于时间的动态红绿切换逻辑
    - 不传参数时默认固定，确保 IntersectionMap 和 IntersectionMapVideos 组件中十字路口显示一致
  2. 兜底数据修复
    - apiGetCrossingDetailData 和特勤监控 API 中 _makeIntersectionConfig 调用补全参数，避免生成随机信号灯状态

src/mock/api.js

@@ -103,9 +103,9 @@ function _camerasToArmTypes(cameras) {
   return result
 }
 
-function _makeIntersectionConfig(id, name) {
+function _makeIntersectionConfig(id, name, { fixedNsGreen } = {}) {
   const phases = ['南北直行', '东西直行', '北单放', '东单放']
-  const nsGreen = Math.random() > 0.5
+  const nsGreen = fixedNsGreen !== undefined ? fixedNsGreen : true
   const countdown = 10 + Math.floor(Math.random() * 50)
   const seed = id ? Array.from(id).reduce((s, c, i) => s + c.charCodeAt(0) * (i + 1), 0) : 0
 
@@ -314,7 +314,7 @@ export async function apiGetPoints(filters = {}) {
  * GET /api/intersections/:id — 路口详情
  * 信号倒计时每次请求动态变化
  */
-export async function apiGetIntersectionData(id) {
+export async function apiGetIntersectionData(id, { fixedNsGreen } = {}) {
   await delay(250)
   const base = DB.intersectionConfigs[id]
   const point = DB.points.find(p => p.id === id)
@@ -324,16 +324,17 @@ export async function apiGetIntersectionData(id) {
   const nowSec = Math.floor(Date.now() / 1000)
   const cycle = 140
   const elapsed = nowSec % cycle
-  const nsGreen = elapsed < cycle / 2
+  const nsGreenVal = fixedNsGreen !== undefined ? fixedNsGreen : true
+  const nsGreen = nsGreenVal
 
   const config = base ? {
     signals: {
-      ns: { ...base.signals.ns, time: nsGreen ? (cycle / 2 - elapsed) : elapsed - cycle / 2, isGreen: nsGreen },
-      ew: { ...base.signals.ew, time: nsGreen ? elapsed : (cycle - elapsed), isGreen: !nsGreen },
+      ns: { ...base.signals.ns, time: Math.max(1, cycle - elapsed), isGreen: nsGreen },
+      ew: { ...base.signals.ew, time: elapsed || 1, isGreen: !nsGreen },
     },
     armsConfig: base.armsConfig,
     cameras: base.cameras,
-  } : _makeIntersectionConfig(id, point ? point.name : id)
+  } : _makeIntersectionConfig(id, point ? point.name : id, { fixedNsGreen: nsGreenVal })
 
   return ok({
     ...config,
@@ -686,7 +687,7 @@ export async function apiUpgradeDevice(id, file) {
  * GET /api/special-task/:id/monitor — 特勤监控面板
  * 信号灯倒计时随真实时间变化
  */
-export async function apiGetSpecialTaskMonitorData(id) {
+export async function apiGetSpecialTaskMonitorData(id, { fixedNsGreen } = {}) {
   await delay(400)
 
   // 用 id 生成稳定 seed，兼容数字/字符串/undefined
@@ -741,8 +742,8 @@ export async function apiGetSpecialTaskMonitorData(id) {
     const jncSeed = Array.from(jnc.id).reduce((s, c, idx) => s + c.charCodeAt(0) * (idx + 1), 0)
     const cycle = [100, 120, 130, 140, 150][jncSeed % 5]
     const elapsed = nowSec % cycle
-    const nsGreen = elapsed < cycle / 2
-    const countdown = nsGreen ? (cycle / 2 - elapsed) : (cycle - elapsed)
+    const nsGreen = fixedNsGreen !== undefined ? fixedNsGreen : true
+    const countdown = Math.max(1, cycle - elapsed)
     const laneSet = lanePresets[jncSeed % lanePresets.length]
 
     // 用摄像机字段结构生成，再推导 cameraType
@@ -785,7 +786,7 @@ export async function apiGetSpecialTaskMonitorData(id) {
 export async function apiGetCrossingPanelData(id) {
   await delay(300)
   const point = DB.points.find(p => p.id === id)
-  const config = DB.intersectionConfigs[id] || _makeIntersectionConfig()
+  const config = DB.intersectionConfigs[id] || _makeIntersectionConfig(id, null, { fixedNsGreen: true })
   const seed = id ? id.charCodeAt(id.length - 1) : 0
 
   const preset = DB.signalTimings[id]
@@ -812,7 +813,7 @@ export async function apiGetCrossingPanelData(id) {
 export async function apiGetCrossingDetailData(id) {
   await delay(350)
   const point = DB.points.find(p => p.id === id)
-  const config = DB.intersectionConfigs[id] || _makeIntersectionConfig()
+  const config = DB.intersectionConfigs[id] || _makeIntersectionConfig(id, null, { fixedNsGreen: true })
 
   // 用 id 的全部字符生成稳定 seed（加权位置避免 charCode 总和碰撞）
   const seed = id ? Array.from(id).reduce((s, c, i) => s + c.charCodeAt(0) * (i + 1), 0) : 0