diff --git a/backend/app/api/maps.py b/backend/app/api/maps.py
index feca4482..7ab6e829 100644
--- a/backend/app/api/maps.py
+++ b/backend/app/api/maps.py
@@ -2,6 +2,7 @@
 from fastapi import APIRouter, Depends, HTTPException, Query
 from sqlalchemy import text
 from sqlalchemy.orm import Session
+from sqlalchemy.orm.attributes import flag_modified
 from typing import Optional
 from datetime import date, datetime, timedelta
 from app.database import get_db
@@ -558,6 +559,8 @@ def add_connection(map_id: int, data: dict, db: Session = Depends(get_db), entit
         "label": data.get("label", ""),
     })
     m.canvas_data["connections"] = conns
+    # D2（2026-10-20）：裸 JSON 列不做就地变更跟踪；显式标脏，与模型层 MutableDict 双保险
+    flag_modified(m, "canvas_data")
     db.commit()
     # updated_at: 供前端采纳为新基准（并发保护 base_updated_at），避免自伤 409
     return {"connections": conns, "updated_at": _stamp(m.updated_at)}
@@ -580,6 +583,8 @@ def delete_connection_by_key(map_id: int, data: dict, db: Session = Depends(get_
         raise HTTPException(404, "连线不存在")
 
     m.canvas_data["connections"] = new_conns
+    # D2（2026-10-20）：换新列表赋值同样不被裸 JSON 列跟踪 ⇒ 显式标脏（根因修复点）
+    flag_modified(m, "canvas_data")
     db.commit()
     return {"connections": new_conns, "removed": {"from": from_id, "to": to_id},
             "updated_at": _stamp(m.updated_at)}
diff --git a/backend/app/main.py b/backend/app/main.py
index b5c98863..b0bd5800 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -41,6 +41,11 @@ app.include_router(kpis.router)
 app.include_router(kpi_governance.router)
 app.include_router(templates.router)
 app.include_router(maps.router)
+# 顺序铁律（2026-10-20 D1 修复）：同前缀族的路由必须把**字面路径段**路由器 include 在
+# 任何 `/{map_id}/<literal>` 参数化路由（objectives.router 的 GET /{map_id}/objectives）之前，
+# 否则 /api/cma/maps/completeness/objectives 会被判 map_id="completeness" → 恒 422。
+app.include_router(map_completeness.router)  # 战略地图数据完备度（口径 CMA-CALIBER-MAP-COMPLETENESS-20261018 v1.0）
+app.include_router(map_summary.router)  # 战略地图摘要条（收入分线/新式毛利率/管理指标 · 口径 CMA-A1 终稿）
 app.include_router(dashboard.router)
 app.include_router(data.router)
 app.include_router(alerts.router)
@@ -56,8 +61,6 @@ app.include_router(action_plans.router)
 app.include_router(alignment.router)
 app.include_router(org.router)
 app.include_router(objectives.router)
-app.include_router(map_completeness.router)  # 战略地图数据完备度（口径 CMA-CALIBER-MAP-COMPLETENESS-20261018 v1.0）
-app.include_router(map_summary.router)  # 战略地图摘要条（收入分线/新式毛利率/管理指标 · 口径 CMA-A1 终稿）
 app.include_router(versions.router)
 app.include_router(budget.router)
 app.include_router(value_sources.router)
diff --git a/backend/app/models/__init__.py b/backend/app/models/__init__.py
index c6e6ca47..79f66bc7 100644
--- a/backend/app/models/__init__.py
+++ b/backend/app/models/__init__.py
@@ -1,5 +1,6 @@
 """管理会计OS 数据模型"""
 from sqlalchemy import Column, Integer, String, Text, Float, DateTime, ForeignKey, Boolean, JSON, func, text, UniqueConstraint, Index, Numeric, Date
+from sqlalchemy.ext.mutable import MutableDict
 from app.database import Base
 
 from app.models.budget_plan import BudgetPlan
@@ -59,7 +60,7 @@ class StrategicMap(Base):
     version = Column(String(20), default="v1.0", comment="版本号")
     status = Column(String(20), default="draft", comment="draft/published")
     dimensions = Column(JSON, nullable=True, comment="四维度和目标列表")
-    canvas_data = Column(JSON, nullable=True, comment="画布连线数据")
+    canvas_data = Column(MutableDict.as_mutable(JSON), nullable=True, comment="画布连线数据")
     created_by = Column(Integer, nullable=True)
     created_at = Column(DateTime, server_default=func.now())
     updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now())
diff --git a/backend/tests/test_map_connection_persistence_20261020.py b/backend/tests/test_map_connection_persistence_20261020.py
new file mode 100644
index 00000000..1e8f8e39
--- /dev/null
+++ b/backend/tests/test_map_connection_persistence_20261020.py
@@ -0,0 +1,128 @@
+"""D2（2026-10-20 fullstack-20261020-strategy-map-3defects-fix）
+
+缺陷：`DELETE /api/cma/maps/{id}/connections` 返回 200 但库里没变（POST 同样不可靠）。
+根因：`StrategicMap.canvas_data` 是裸 `Column(JSON)`，无变更跟踪；接口用
+「`m.canvas_data["connections"] = new_conns`」就地改，flush 时该列未被判脏 ⇒ 不写库。
+
+判据铁律（任务 §1.2）：**不能**用「响应体里 connections 变短了」当落库证据 ——
+必须新开 session 用原生 SQL 复读 `canvas_data`。
+"""
+import json
+
+from sqlalchemy import text
+
+from app.models import StrategicMap
+
+
+def _raw_canvas_data(map_id: int) -> dict:
+    """**新 session + 原生 SQL** 复读（不复用请求内 session）。"""
+    from tests.conftest import TEST_SESSION_LOCAL
+
+    session = TEST_SESSION_LOCAL()
+    try:
+        row = session.execute(
+            text("SELECT canvas_data FROM strategic_maps WHERE id = :mid"), {"mid": map_id}
+        ).first()
+        assert row is not None, f"strategic_maps.id={map_id} 不存在"
+        raw = row[0]
+    finally:
+        session.close()
+    if isinstance(raw, (str, bytes)):
+        return json.loads(raw)
+    return raw or {}
+
+
+def _pairs(canvas: dict):
+    return [(c.get("from"), c.get("to")) for c in (canvas.get("connections") or [])]
+
+
+def test_add_connection_persists_across_sessions(client, db):
+    from tests.conftest import auth_header, create_test_map, create_test_user, get_token_for_user
+
+    create_test_user(db)
+    m = create_test_map(db, entity_id=1)  # canvas_data={"connections": []}
+    db.commit()
+    token = get_token_for_user(client)
+    h = auth_header(token)
+
+    resp = client.post(
+        f"/api/cma/maps/{m.id}/connections",
+        json={"from": "learning-0", "to": "process-0"},
+        headers=h,
+    )
+    assert resp.status_code == 200, resp.text
+    assert ("learning-0", "process-0") in _pairs(_raw_canvas_data(m.id)), (
+        "POST /connections 返回 200 但新 session 原生 SQL 读不到该连线（未落库）"
+    )
+
+
+def test_delete_connection_persists_across_sessions(client, db):
+    from tests.conftest import auth_header, create_test_map, create_test_user, get_token_for_user
+
+    create_test_user(db)
+    m = create_test_map(
+        db,
+        entity_id=1,
+        canvas_data={"connections": [
+            {"from": "learning-0", "to": "process-0", "style": "solid", "effect": "positive", "label": ""},
+            {"from": "process-0", "to": "customer-0", "style": "solid", "effect": "positive", "label": ""},
+        ]},
+    )
+    db.commit()
+    token = get_token_for_user(client)
+    h = auth_header(token)
+
+    resp = client.request(
+        "DELETE",
+        f"/api/cma/maps/{m.id}/connections",
+        json={"from": "learning-0", "to": "process-0"},
+        headers=h,
+    )
+    assert resp.status_code == 200, resp.text
+
+    persisted = _pairs(_raw_canvas_data(m.id))
+    assert ("learning-0", "process-0") not in persisted, (
+        f"DELETE 返回 200 但新 session 原生 SQL 仍读到已删连线：{persisted}"
+    )
+    assert ("process-0", "customer-0") in persisted, "无关连线被误删"
+
+
+def test_delete_missing_connection_still_404(client, db):
+    """负测：删除不存在的 from/to 仍 404（不得因标脏改动变成 200）。"""
+    from tests.conftest import auth_header, create_test_map, create_test_user, get_token_for_user
+
+    create_test_user(db)
+    m = create_test_map(db, entity_id=1)
+    db.commit()
+    token = get_token_for_user(client)
+    h = auth_header(token)
+
+    resp = client.request(
+        "DELETE",
+        f"/api/cma/maps/{m.id}/connections",
+        json={"from": "learning-9", "to": "process-9"},
+        headers=h,
+    )
+    assert resp.status_code == 404, resp.text
+
+
+def test_canvas_data_mutation_tracked_by_mutable_dict(db):
+    """模型层双保险：MutableDict 包装后，**不经 flag_modified** 的 dict 赋值也应落库。
+
+    说明：`MutableDict.as_mutable(JSON)` 返回的仍是 JSON 类型实例（跟踪靠 mapper 级
+    attribute 事件 + coerce），因此这里用**行为断言**而不是断言列类型类名。
+    """
+    m = StrategicMap(title="MutableDict 行为验证", entity_id=1, canvas_data={"connections": []})
+    db.add(m)
+    db.commit()
+    mid = m.id
+    db.expire_all()
+
+    loaded = db.query(StrategicMap).filter(StrategicMap.id == mid).first()
+    # 就地改 dict（等价于接口里的 `m.canvas_data["connections"] = new_conns`）
+    loaded.canvas_data["connections"] = [{"from": "learning-0", "to": "process-0"}]
+    db.commit()  # 不调用 flag_modified
+
+    assert ("learning-0", "process-0") in _pairs(_raw_canvas_data(mid)), (
+        "canvas_data 未被 MutableDict 跟踪：dict 赋值后 commit 未落库"
+    )
diff --git a/backend/tests/test_map_route_shadowing_20261020.py b/backend/tests/test_map_route_shadowing_20261020.py
new file mode 100644
index 00000000..be76e034
--- /dev/null
+++ b/backend/tests/test_map_route_shadowing_20261020.py
@@ -0,0 +1,108 @@
+"""D1（2026-10-20 fullstack-20261020-strategy-map-3defects-fix）
+
+缺陷：`GET /api/cma/maps/completeness/objectives` 恒 422。
+根因（项目Bot 复核修正）：`main.py` 先 include 的 `objectives.router`
+（prefix `/api/cma/maps`，`GET /{map_id}/objectives`）把 `map_id="completeness"`
+当 int 解析 → 422；真抢占者不是 `maps.router`。
+
+修复：`map_completeness.router` / `map_summary.router` 前移到 `objectives.router` 之前。
+本文件钉住三件事：
+  1) 该 path 的首个 FULL match 落在 `app.api.map_completeness`（比 200/401 更硬，不依赖 DB）；
+  2) `/completeness/summary` 不回归；
+  3) `/maps/{map_id}/objectives` 仍命中 `app.api.objectives`；
+  4) 同前缀族全量巡检：任何字面路径路由都不得被先注册的参数化路由吃掉。
+"""
+from pathlib import Path
+
+from fastapi.routing import APIRoute
+from starlette.routing import Match
+
+from app.main import app
+
+COMPLETENESS_OBJECTIVES = "/api/cma/maps/completeness/objectives"
+
+
+def _first_full_match(path: str, method: str = "GET"):
+    """按注册顺序返回首个 FULL match 的 route（= Starlette 实际分发结果）。"""
+    scope = {"type": "http", "method": method, "path": path, "headers": []}
+    for route in app.routes:
+        if not hasattr(route, "matches"):
+            continue
+        match, _child = route.matches(scope)
+        if match == Match.FULL:
+            return route
+    return None
+
+
+def _ep(route) -> str:
+    endpoint = getattr(route, "endpoint", None)
+    return f"{getattr(endpoint, '__module__', '?')}.{getattr(endpoint, '__name__', '?')}"
+
+
+def test_app_imported_from_this_worktree():
+    """防呆：pytest.ini 的 pythonpath 指向部署树，必须断言用的是当前工作区代码。"""
+    from app import main as app_main
+
+    repo_backend = Path(__file__).resolve().parents[1]
+    assert Path(app_main.__file__).resolve().is_relative_to(repo_backend), (
+        f"导入了非本工作区的 app.main：{app_main.__file__}（期望在 {repo_backend} 下）"
+    )
+
+
+def test_completeness_objectives_route_resolves_to_map_completeness():
+    route = _first_full_match(COMPLETENESS_OBJECTIVES)
+    assert route is not None, f"没有路由匹配 {COMPLETENESS_OBJECTIVES}"
+    assert _ep(route) == "app.api.map_completeness.completeness_objectives", (
+        f"{COMPLETENESS_OBJECTIVES} 被抢先解析为 {_ep(route)}"
+    )
+    assert getattr(route, "path", None) == COMPLETENESS_OBJECTIVES
+
+
+def test_completeness_summary_not_regressed():
+    route = _first_full_match("/api/cma/maps/completeness/summary")
+    assert route is not None
+    assert _ep(route) == "app.api.map_completeness.completeness_summary", _ep(route)
+
+
+def test_map_summary_not_shadowed():
+    route = _first_full_match("/api/cma/maps/summary")
+    assert route is not None
+    assert _ep(route) == "app.api.map_summary.map_summary", _ep(route)
+
+
+def test_map_objectives_endpoint_not_regressed():
+    route = _first_full_match("/api/cma/maps/65/objectives")
+    assert route is not None
+    assert _ep(route) == "app.api.objectives.list_objectives", _ep(route)
+
+
+def test_no_literal_path_shadowed_in_maps_prefix_family():
+    """同前缀族全量巡检：/api/cma/maps* 下所有**字面**路径的首个匹配必须是自己。"""
+    family = [
+        r for r in app.routes
+        if isinstance(r, APIRoute)
+        and r.path.startswith("/api/cma/maps")
+        and "{" not in r.path
+    ]
+    assert family, "未发现 /api/cma/maps* 字面路径路由，巡检面为空（异常）"
+
+    problems = []
+    for r in family:
+        for method in sorted((r.methods or set()) - {"HEAD", "OPTIONS"}):
+            first = _first_full_match(r.path, method)
+            if first is not r:
+                problems.append(f"{method} {r.path} -> {_ep(first)}（应为 {_ep(r)}）")
+    assert not problems, "同前缀族路由被抢占：\n" + "\n".join(problems)
+
+
+def test_completeness_objectives_http_not_422(client, db):
+    """端到端：带凭据请求不得出现 loc=["path","map_id"] / input="completeness" 的 422。"""
+    from tests.conftest import auth_header, create_test_user, get_token_for_user
+
+    create_test_user(db)
+    token = get_token_for_user(client)
+    resp = client.get(COMPLETENESS_OBJECTIVES, headers=auth_header(token))
+    assert resp.status_code != 422, resp.text
+    assert resp.status_code == 200, resp.text
+    body = resp.json()
+    assert "objectives" in body or isinstance(body, dict)
diff --git a/frontend/src/views/MapCanvas.vue b/frontend/src/views/MapCanvas.vue
index 58d6420a..9d1b02cb 100644
--- a/frontend/src/views/MapCanvas.vue
+++ b/frontend/src/views/MapCanvas.vue
@@ -994,10 +994,35 @@ function onTreeDragStart(payload: { dimKey: string; index: number; obj: any }) {
 }
 function onTreeDragOver(e: DragEvent) {
   if (!treeDragSource.value) return
-  const el = document.elementFromPoint(e.clientX, e.clientY)?.closest('[data-node-key]') as HTMLElement | null
-  const key = el?.getAttribute('data-node-key') || null
+  const key = hitTestTreeNodeAt(e.clientX, e.clientY)
   dragConnectTarget.value = key && key !== treeDragSource.value.key ? key : null
 }
+
+/**
+ * D3（2026-10-20）：窄视口下 .kp-panel 是 fixed + z-index:1000 的浮层，会盖住画布主体；
+ * 旧实现用 document.elementFromPoint() 取节点 —— 命中面板时 .closest('[data-node-key]') 恒 null，
+ * 拖拽建连线必走 cancelLink()。改为**几何命中**：直接遍历画布内全部 [data-node-key]，
+ * 用 getBoundingClientRect() 做包含判断（rect 已含 transform: scale，与 clientX/Y 同坐标系）；
+ * 多点重叠时取中心距拖拽点最近者。**不再回退 elementFromPoint**（否则窄屏复发）。
+ * 性能：19 个节点的 rect 遍历一帧一次 ≈ 微秒级，无需 rAF/节流，避免节流造成 drop 时刻判据滞后。
+ */
+function hitTestTreeNodeAt(x: number, y: number): string | null {
+  const box = scrollWrapRef.value
+  if (!box) return null
+  const nodes = box.querySelectorAll<HTMLElement>('[data-node-key]')
+  let bestKey: string | null = null
+  let bestDist = Number.POSITIVE_INFINITY
+  for (let i = 0; i < nodes.length; i++) {
+    const r = nodes[i].getBoundingClientRect()
+    if (r.width === 0 && r.height === 0) continue          // 隐藏层/折叠层
+    if (x < r.left || x > r.right || y < r.top || y > r.bottom) continue
+    const dx = x - (r.left + r.width / 2)
+    const dy = y - (r.top + r.height / 2)
+    const d = dx * dx + dy * dy
+    if (d < bestDist) { bestDist = d; bestKey = nodes[i].getAttribute('data-node-key') }
+  }
+  return bestKey
+}
 function onTreeDragLeave(e: DragEvent) {
   const related = (e as any).relatedTarget as Node | null
   const box = scrollWrapRef.value