新增：SFTP直连+连接池+autoConnect+文件服务器端口自动回退

- SFTP模块：连接/断开/文件CRUD/系统信息采集/base64二进制写入
- 连接池：多服务器同时在线，瞬间切换profile
- autoConnect：启动时自动连接所有非本地服务器
- 端口自动回退：listenWithFallback消除TOCTOU，解决端口冲突崩溃
- 文件服务器URL集中管理：file-server.ts消除8+处硬编码端口
- Sidebar设置面板：添加服务器/自动连接/自动刷新开关
- 修复：validateFilePath越界panic、正则预编译
- 修复：注释准确性（RemoveAll/端口8073/动态端口文档）

frontend/package-lock.json

@@ -2138,7 +2138,6 @@
       "resolved": "https://registry.npmmirror.com/chevrotain/-/chevrotain-12.0.0.tgz",
       "integrity": "sha512-csJvb+6kEiQaqo1woTdSAuOWdN0WTLIydkKrBnS+V5gZz0oqBrp4kQ35519QgK6TpBThiG3V1vNSHlIkv4AglQ==",
       "license": "Apache-2.0",
-      "peer": true,
       "dependencies": {
         "@chevrotain/cst-dts-gen": "12.0.0",
         "@chevrotain/gast": "12.0.0",
@@ -2311,7 +2310,6 @@
       "resolved": "https://registry.npmmirror.com/cytoscape/-/cytoscape-3.33.3.tgz",
       "integrity": "sha512-Gej7U+OKR+LZ8kvX7rb2HhCYJ0IhvEFsnkud4SB1PR+BUY/TsSO0dmOW59WEVLu51b1Rm+gQRKoz4bLYxGSZ2g==",
       "license": "MIT",
-      "peer": true,
       "engines": {
         "node": ">=0.10"
       }
@@ -2712,7 +2710,6 @@
       "resolved": "https://registry.npmmirror.com/d3-selection/-/d3-selection-3.0.0.tgz",
       "integrity": "sha512-fmTRWbNMmsmWq6xJV8D19U/gw/bwrHfNXxrIN+HfZgnzqTHp9jOmKMhsTUjXOJnZOdZY9Q28y4yebKzqDKlxlQ==",
       "license": "ISC",
-      "peer": true,
       "engines": {
         "node": ">=12"
       }
@@ -3737,7 +3734,6 @@
       "integrity": "sha512-J9qZyW++QK/09NyN/zeO0dG/1GdGfyp9lV8ajHnRVLfo/uFsbji5mHnDgn/qYdUHyCkM2N+8VyspgZclfAh0eQ==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "@types/estree": "1.0.8"
       },
@@ -4186,7 +4182,6 @@
       "integrity": "sha512-Bby3NOsna2jsjfLVOHKes8sGwgl4TT0E6vvpYgnAYDIF/tie7MRaFthmKuHx1NSXjiTueXH3do80FMQgvEktRg==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "esbuild": "^0.27.0",
         "fdir": "^6.5.0",
@@ -4310,7 +4305,6 @@
       "resolved": "https://registry.npmmirror.com/vue/-/vue-3.5.33.tgz",
       "integrity": "sha512-1AgChhx5w3ALgT4oK3acm2Es/7jyZhWSVUfs3rOBlGQC0rjEDkS7G4lWlJJGGNQD+BV3reCwbQrOe1mPNwKHBQ==",
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "@vue/compiler-dom": "3.5.33",
         "@vue/compiler-sfc": "3.5.33",