feat(amneziawg): support persistent keepalive ranges (#6881)

AmneziaWG clients accept a randomised PersistentKeepalive range such as 15-25,
which makes keepalive timing harder to fingerprint; the panel only stored a
single number. A client's keepalive may now be a range, validated the way
AmneziaWG parses it. The downloadable .conf and vpn:// profile carry the range,
Clash/Mihomo output gets its lower bound, and plain WireGuard stays scalar-only.
The range lives in an additive wg_keep_alive_range column, so the integer
column and an older panel binary keep working after a rollback.

frontend/src/generated/examples.ts

@@ -424,7 +424,7 @@ export const EXAMPLES: Record<string, unknown> = {
     "forwardedPorts": "",
     "group": "",
     "id": "",
-    "keepAlive": null,
+    "keepAlive": 0,
     "limitIp": 0,
     "password": "",
     "preSharedKey": "",

frontend/src/generated/schemas.ts

@@ -1733,9 +1733,15 @@ export const SCHEMAS: Record<string, unknown> = {
         "type": "string"
       },
       "keepAlive": {
-        "description": "Seconds between PersistentKeepalive packets; 0 sends none, omit to keep the stored value",
-        "nullable": true,
-        "type": "integer"
+        "description": "Numeric values or AmneziaWG ranges; 0 disables, omission preserves.",
+        "oneOf": [
+          {
+            "type": "integer"
+          },
+          {
+            "type": "string"
+          }
+        ]
       },
       "limitIp": {
         "description": "IP limit for this client",
@@ -1955,7 +1961,15 @@ export const SCHEMAS: Record<string, unknown> = {
         "type": "integer"
       },
       "keepAlive": {
-        "type": "integer"
+        "description": "Numeric values or AmneziaWG ranges.",
+        "oneOf": [
+          {
+            "type": "integer"
+          },
+          {
+            "type": "string"
+          }
+        ]
       },
       "limitHwid": {
         "type": "integer"

frontend/src/generated/types.ts

@@ -420,7 +420,7 @@ export interface Client {
   forwardedPorts?: string;
   group?: string;
   id?: string;
-  keepAlive?: number | null;
+  keepAlive?: number | string;
   limitIp: number;
   password?: string;
   preSharedKey?: string;
@@ -471,7 +471,7 @@ export interface ClientRecord {
   forwardedPorts: string;
   group: string;
   id: number;
-  keepAlive: number;
+  keepAlive: number | string;
   limitHwid: number;
   limitIp: number;
   password: string;

frontend/src/generated/zod.ts

@@ -441,7 +441,7 @@ export const ClientSchema = z.object({
   forwardedPorts: z.string().optional(),
   group: z.string().optional(),
   id: z.string().optional(),
-  keepAlive: z.number().int().nullable().optional(),
+  keepAlive: z.union([z.number().int(), z.string()]).optional(),
   limitIp: z.number().int(),
   password: z.string().optional(),
   preSharedKey: z.string().optional(),
@@ -495,7 +495,7 @@ export const ClientRecordSchema = z.object({
   forwardedPorts: z.string(),
   group: z.string(),
   id: z.number().int(),
-  keepAlive: z.number().int(),
+  keepAlive: z.union([z.number().int(), z.string()]),
   limitHwid: z.number().int(),
   limitIp: z.number().int(),
   password: z.string(),