feat(system): add system status and software info endpoints

Add new endpoints to expose system status and software information:
- /system/getStatus returns current system status (online/offline)
- /system/getSoftwareInfo returns software version and build details
Update API documentation to include new endpoints

docs/api.md

@@ -23,11 +23,73 @@ All API responses are returned in JSON format:
 - For all requests: Authentication token and timestamp are sent in HTTP headers (prefixed with `X-`)
 - For **POST** requests: Other data is sent in the request body as JSON
 - For **GET** requests: All data is sent in HTTP headers (prefixed with `X-`)
-- All requests require authentication (except `/register` and `/login`)
+- All requests require authentication (except `/register`, `/login`, `/system/getStatus`, `/system/getSoftwareInfo`)
 - Timestamps are in milliseconds (Unix timestamp)
 
 ---
 
+## Get System Status
+
+**Endpoint:** `/system/getStatus`  
+**Method:** GET  
+**Auth Required:** No  
+**Permission Level:** None
+
+Get the current system status.
+
+**Response:**
+```json
+{
+  "success": true,
+  "message": "getStatus",
+  "data": {
+    "Status": "Online"
+  }
+}
+```
+
+| Field | Type | Description |
+|-------|------|-------------|
+| Status | string | System status: "Online" or "Offline" |
+
+---
+
+## Get Software Info
+
+**Endpoint:** `/system/getSoftwareInfo`  
+**Method:** GET  
+**Auth Required:** No  
+**Permission Level:** None
+
+Get software version and build information.
+
+**Response:**
+```json
+{
+  "success": true,
+  "message": "getSoftwareInfo",
+  "data": {
+    "Name": "Super-frpc",
+    "Version": "0.0.1",
+    "Developer": "Madobi Nanami",
+    "BuildVer": 1,
+    "Description": "",
+    "BuildType": "debug"
+  }
+}
+```
+
+| Field | Type | Description |
+|-------|------|-------------|
+| Name | string | Software name |
+| Version | string | Software version |
+| Developer | string | Developer name |
+| BuildVer | int16 | Build version number |
+| Description | string | Software description |
+| BuildType | string | Build type: "debug" or "release" |
+
+---
+
 ## Register User
 
 **Endpoint:** `/register`