feat(ECR-014): MembershipPlan 套餐配置并 Closed

membership_plans 表、admin 套餐页、Grant/CreateOrder 读表；
Loop continuous 自动 Approve/Closed。Next：ECR-015 RedemptionCode。

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/CONTRACT_DIFF/ECR-014.yaml

@@ -0,0 +1,36 @@
+ecr: ECR-014
+capability: CommerceEntitlement
+bounded_context: Membership_Orders
+parent: WAVE0-FROZEN
+predecessor: ECR-013B
+change:
+  type: additive
+breaking_change: false
+migration_required: true
+compatibility_notes: >
+  New membership_plans table seeded with month/quarter/year.
+  Grant/CreateOrder read duration/amount from table with hardcoded fallback.
+  Additive RBAC permissions.
+
+entities:
+  - name: MembershipPlan
+    before: null
+    after:
+      fields: [code, title, duration_days, amount_cents, active, updated_at]
+      codes: [month, quarter, year]
+
+apis:
+  - method: GET
+    path: /api/v1/admin/membership-plans
+    change: added
+  - method: GET
+    path: /api/v1/admin/membership-plans/{code}
+    change: added
+  - method: PUT
+    path: /api/v1/admin/membership-plans/{code}
+    change: added
+
+security_impact:
+  - "admin.membership.plans.read/write"
+observability_impact:
+  - "AuditLog membership.plans.update"