feat(mapcanvas): 田字格2x2布局+拖拽辅助(合法高亮/灰显/吸附)+连接管理面板+zoom transform缩放+连线rAF节流

frontend/src/components/strategy-map/StrategyLayer.vue

@@ -40,6 +40,7 @@
               :is-linking-source="linkingFromKey === `${layerKey}-${index}`"
               :is-linking-target="!!linkingFromKey && linkingFromKey !== `${layerKey}-${index}`"
               :is-drag-connect-target="dragConnectTarget === `${layerKey}-${index}`"
+              :link-eligibility="linkEligibilityMap?.[`${layerKey}-${index}`] ?? null"
               :icon-map="iconMap"
               :kpi-name-map="kpiNameMap"
               :all-kpis="allKpis"
@@ -89,6 +90,8 @@ const props = defineProps<{
   objectives: any[]
   linkingFromKey?: string | null
   dragConnectTarget?: string | null
+  /** 拖拽连线时的目标合法性：valid=合法高亮 / forbidden=反方向灰显 */
+  linkEligibilityMap?: Record<string, 'valid' | 'forbidden'>
   iconMap?: Record<string, string>
   kpiNameMap?: Record<string, string>
   allKpis?: any[]