fix: permission checks for speedId and inPort + multi-node IP constraints (#261)

* feat: restrict user permissions and multi-node IP constraints

- Non-admin users cannot set speedId or inPort on forward create/update
- Multi-entrance tunnels disable custom listen IP for forwards
- Multi-exit tunnels disable custom connect IP
- Multi-node hop chains disable custom connect IP per hop
- Remove tunnel-first-IP fallback in forward ingress resolution
- Add contract tests for non-admin permission restrictions

Entire-Checkpoint: 133693290660

* fix: allow non-admin users to submit null speedId and zero inPort

- Backend: Check speedId is not nil before rejecting non-admin requests
- Backend: Only reject inPort if value > 0 for non-admin users
- Frontend: Only include speedId and inPort in payload for admin users
- Tests: Add contract tests for null speedId and zero inPort cases

.entire/metadata/ses_34d1fa4b1ffeH4sVbjXkh5P6IY/context.md

@@ -0,0 +1,41 @@
+# Session Context
+
+Session ID: ses_34d1fa4b1ffeH4sVbjXkh5P6IY
+Commit Message: 实施
+
+## Prompts
+
+### Prompt 1
+
+转发导入，ny兼容格式，不要选择入口，改成选择隧道，修改兼容一下
+
+### Prompt 2
+
+自动分配端口（推荐）
+
+### Prompt 3
+
+实施
+
+## Summary
+
+已实施完成，这次改动把 `ny` 导入完全对齐到“选隧道”流程，并按你指定支持“端口缺失自动分配”。
+
+- `ny` 解析兼容增强：支持字段别名、可选端口  
+  - 修改 `vite-frontend/src/pages/forward/import-format.ts`  
+  - `listen_port` 现在允许为 `null`（缺失即自动分配）  
+  - 兼容字段：`dest/dst/target/targets`、`listen_port/listenPort/port/in_port/inPort`、`name/forward_name/forwardName`  
+  - `dest` 支持数组或逗号分隔字符串，统一归一化  
+- 导入 UI 文案已同步更新（强调按所选隧道导入 + 端口可省略）  
+  - 修改 `vite-frontend/src/pages/forward.tsx:4623`、`vite-frontend/src/pages/forward.tsx:4699`  
+- 测试已补齐并通过  
+  - 修改 `vite-frontend/src/pages/forward/import-format.test.ts`  
+  - 新增用例：缺失端口自动分配、别名字段兼容、`inPort: null` 映射  
+- 计划文档已新增并完成勾选  
+  - `plans/002-ny-import-tunnel-selection-compat.md`
+
+验证结果：
+- `npm run build`（`vite-frontend`）通过
+- `node --test src/pages/forward/import-format.test.ts` 7/7 通过
+
+如果你要，我下一步可以直接帮你提交一个规范 commit。