fix(maps): 画布连线键与目标改名解耦（objective_id 锚定）+ nodeRefs 位置兜底 + 保守反错绑断言（P3）

- map_connections 读侧以 from/to_objective_id 反查当前 dimensions 树定位节点，改名/重排不再静默断线
- 悬停/拖拽期 map_objectives 未返回时按位置兜底（仅同层同序位有效），并记录 stale_objective_id
- 新增 tests/test_conn_key_rename_stability.py（含 2 条保守反错绑负测用例）
- 零 DDL、零 health_score 改动（问3=A）

frontend/src/views/MapCanvas.vue

@@ -210,6 +210,7 @@
       :layer-refs="layerRefs"
       :node-refs="compiledNodeRefs"
       :layer-keys="layerKeysOrdered"
+      :conn-keys="connKeys"
       :connections="connections"
       :temp-line="tempLine"
       :container-key="recalcTrigger"
@@ -319,6 +320,8 @@ import MapTargetTree from "../components/strategy-map/MapTargetTree.vue"
 import MapNodeDetail from "../components/strategy-map/MapNodeDetail.vue"
 import MapCompleteness from "../components/strategy-map/MapCompleteness.vue"
 import ConnectionLines from "../components/strategy/ConnectionLines.vue"
+// P3：连线端点解析键（`层-序号`）—— 目标改名后线仍指向同一节点
+import { buildKeyIndex, type ConnectionKeyEntry } from "../utils/connKeys"
 import MapCanvasToolbar from "../components/map-canvas/MapCanvasToolbar.vue"
 import MapDimensionFilter from "../components/map-canvas/MapDimensionFilter.vue"
 import CaliberBadge from "../components/CaliberBadge.vue"
@@ -403,6 +406,8 @@ const undoStack = ref<{ dimensions: any; connections: any[] }[]>([])
 
 // 连线
 const connections = ref<any[]>([])
+/** P3：服务端解析键（与 connections 逐下标对齐）；空 ⇒ 回落原标识串（历史/降级） */
+const connKeys = ref<ConnectionKeyEntry[]>([])
 const linkingFrom = ref<{ key: string; obj: any } | null>(null)
 const tempLine = ref<{ x1: number; y1: number; x2: number; y2: number } | null>(null)
 const dragConnectTarget = ref<string | null>(null)
@@ -797,6 +802,22 @@ watch(zoomLevel, () => {
   nextTick(() => connectionLinesRef.value?.recalcAll())
 })
 
+// ── P3：服务端解析键 ──
+// 为什么必须取服务端：canvas_data 里存的是写入时刻的标识串（`层:中文名`），
+// 目标改名后名字串失效；服务端能由 from/to_objective_id 反查当前 `${层}-${序号}`。
+// 取不到（接口异常/离线）⇒ 置空，画布回落原标识串，行为与改造前一致（不更坏）。
+async function refreshConnKeys() {
+  const id = selectedMap.value
+  if (!id) { connKeys.value = []; return }
+  try {
+    const r: any = await api.get(`/maps/${id}/connections`)
+    const serverConns = r?.data?.connections || []
+    connKeys.value = buildKeyIndex(loadedCanvas || connections.value || [], serverConns)
+  } catch (e) {
+    connKeys.value = []
+  }
+}
+
 // ── 画布加载 ──
 function loadCanvas() {
   caliberFacts.value = caliberGapFor(currentCaliberEntityId())
@@ -842,6 +863,7 @@ function loadCanvas() {
     loadedDims = deepClone(dimensions)
     connections.value = map?.canvas_data?.connections || []
     loading.value = false
+    refreshConnKeys()
     nextTick(() => {
       triggerRecalc()
       updateGridMode()
@@ -982,6 +1004,7 @@ function undoLast() {
   connections.value = JSON.parse(JSON.stringify(snap.connections))
   selectedNode.value = null
   markDirty()
+  refreshConnKeys()   // P3：撤销可能改动目标顺序/名字，解析键随之刷新
   nextTick(() => { triggerRecalc(); updateZoomWrapHeight(); loadObjectiveLevels() })
   ElMessage.success('已撤销上一步')
 }
@@ -1716,6 +1739,9 @@ async function saveCanvas(silent?: boolean) {
     if (res?.updated_at) baseUpdatedAt.value = res.updated_at   // 采纳服务端新基准
     refreshBaselines(res?.dimensions)                           // 基线回到服务端现值（响应体为权威）
     markClean()
+    // P3：保存后刷新解析键（改名/调序都会让 `${层}-${序号}` 变，线要跟着节点走）
+    if (payload.canvas_data) loadedCanvas = deepClone(connections.value)
+    refreshConnKeys()
     if (!silent) ElMessage.success("已保存")
   } catch (e: any) {
     if (e?.response?.status === 409) {
@@ -1742,6 +1768,8 @@ async function saveConnections() {
       base_updated_at: currentBaseStamp(),
     })
     if (res?.updated_at) baseUpdatedAt.value = res.updated_at
+    loadedCanvas = deepClone(connections.value)
+    refreshConnKeys()   // P3：连线新增/删除后服务端重算解析键
   } catch (e: any) {
     if (e?.response?.status === 409) {
       autoSaveBlocked.value = true