修复开发环境截图URL缺少/dev-api前缀问题

img标签src不走axios，需手动加VUE_APP_BASE_API前缀，
否则开发环境下请求不经过devServer代理直接404

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

web/src/views/cameraConfig/roiConfig.vue

@@ -114,7 +114,8 @@ export default {
     this.cameraId = decodeURIComponent(this.$route.params.cameraId)
     this.srcUrl = this.$route.query.srcUrl || ''
     if (this.srcUrl) {
-      this.snapUrl = `/api/ai/roi/snap?url=${encodeURIComponent(this.srcUrl)}`
+      const base = process.env.NODE_ENV === 'development' ? process.env.VUE_APP_BASE_API : ''
+      this.snapUrl = `${base}/api/ai/roi/snap?url=${encodeURIComponent(this.srcUrl)}`
     }
     this.loadRois()
   },
@@ -146,7 +147,8 @@ export default {
     },
     refreshSnap() {
       if (this.srcUrl) {
-        this.snapUrl = `/api/ai/roi/snap?url=${encodeURIComponent(this.srcUrl)}&t=${Date.now()}`
+        const base = process.env.NODE_ENV === 'development' ? process.env.VUE_APP_BASE_API : ''
+        this.snapUrl = `${base}/api/ai/roi/snap?url=${encodeURIComponent(this.srcUrl)}&t=${Date.now()}`
       }
     },
     onRoiDrawn(data) {