fix: 同步 edit_plans/edit_templates 测试断言到 Phase 8 config 标准化结构

Phase 8 引入 normalize_plan_config/normalize_template_config 后，
API 会将 config 扩展为完整的结构化默认值（cover/title/subtitle/bgm），
但测试断言仍使用旧的简单 dict 格式，导致 4 个用例失败。

修复方式：导入 normalize_* 函数，断言改为期望标准化后的 config。

修复用例：
- test_create_success (plans)
- test_create_minimal (plans)
- test_update_config (plans)
- test_create_with_all_fields (templates)

tests/unit/test_edit_plans_api.py

@@ -28,6 +28,7 @@ sys.path.insert(0, str(Path(__file__).resolve().parents[2] / "apps" / "api"))
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
 
+from packages.domain.config_schemas import normalize_plan_config
 from packages.domain.edit_plan import EditPlan, EditPlanStatus
 
 # ---------------------------------------------------------------------------
@@ -190,7 +191,7 @@ class TestCreatePlan:
         assert data["template_id"] == "tpl-001"
         assert data["status"] == "draft"
         assert data["total_duration"] == 60.0
-        assert data["config"] == {"bgm": "happy"}
+        assert data["config"] == normalize_plan_config({"bgm": "happy"})
         assert "id" in data
         assert "created_at" in data
 
@@ -202,7 +203,7 @@ class TestCreatePlan:
         )
         assert resp.status_code == 201
         data = resp.json()
-        assert data["config"] == {}
+        assert data["config"] == normalize_plan_config(None)
         assert data["total_duration"] == 0.0
 
     def test_create_empty_name_returns_422(self, client):
@@ -386,7 +387,7 @@ class TestUpdatePlan:
             json={"config": {"bgm": "sad", "transition": "fade"}},
         )
         assert resp.status_code == 200
-        assert resp.json()["config"] == {"bgm": "sad", "transition": "fade"}
+        assert resp.json()["config"] == normalize_plan_config({"bgm": "sad", "transition": "fade"})
 
     def test_update_total_duration(self, client):
         c, repo = client

tests/unit/test_edit_templates_api.py

@@ -28,6 +28,7 @@ from fastapi.testclient import TestClient
 
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "apps", "api"))
 
+from packages.domain.config_schemas import normalize_template_config
 from packages.domain.edit_template import EditTemplate, EditTemplateStatus
 
 # ── Stub Repository ───────────────────────────────────────────────────────────
@@ -276,7 +277,7 @@ class TestCreateTemplate:
         assert data["name"] == "完整模板"
         assert data["description"] == "完整描述"
         assert data["template_type"] == "vlog"
-        assert data["config"] == {"key": "value"}
+        assert data["config"] == normalize_template_config({"key": "value"})
         assert data["preview_url"] == "https://example.com/preview.mp4"
         assert data["sort_weight"] == 10