fix(nodes): Set Cert from Panel uses the node's own web cert for node inbounds

For an inbound deployed to a node, the button read the central panel's webCertFile/webKeyFile and inserted paths that don't exist on the node, crashing the node's Xray on startup.

Add a token-accessible GET /panel/api/server/getWebCertFiles that returns a panel's own web cert/key paths, Remote.GetWebCertFiles to fetch it from a node, and GET /panel/api/nodes/webCert/:id to proxy it. setCertFromPanel now calls the node endpoint for a node-assigned inbound and the local settings otherwise, warning instead of inserting wrong paths on error/empty.

Fixes #4854

frontend/src/pages/api-docs/endpoints.ts

@@ -313,6 +313,12 @@ export const sections: readonly Section[] = [
         summary: 'Generate a fresh UUID v4. Convenience helper for client IDs.',
         response: '{\n  "success": true,\n  "obj": "550e8400-e29b-41d4-a716-446655440000"\n}',
       },
+      {
+        method: 'GET',
+        path: '/panel/api/server/getWebCertFiles',
+        summary: 'Return this panel\'s own web TLS certificate and key file paths. The central panel calls it on a node (via the node API token) so "Set Cert from Panel" fills a node-assigned inbound with paths that exist on the node.',
+        response: '{\n  "success": true,\n  "obj": {\n    "webCertFile": "/root/cert/example.com/fullchain.pem",\n    "webKeyFile": "/root/cert/example.com/privkey.pem"\n  }\n}',
+      },
       {
         method: 'GET',
         path: '/panel/api/server/getNewX25519Cert',
@@ -741,6 +747,15 @@ export const sections: readonly Section[] = [
           { name: 'id', in: 'path', type: 'number', desc: 'Node ID.' },
         ],
       },
+      {
+        method: 'GET',
+        path: '/panel/api/nodes/webCert/:id',
+        summary: 'Fetch a node\'s own web TLS certificate/key file paths (proxied to the node). Used by the inbound form\'s "Set Cert from Panel" so a node-assigned inbound gets paths that exist on the node, not the central panel.',
+        params: [
+          { name: 'id', in: 'path', type: 'number', desc: 'Node ID.' },
+        ],
+        response: '{\n  "success": true,\n  "obj": {\n    "webCertFile": "/root/cert/example.com/fullchain.pem",\n    "webKeyFile": "/root/cert/example.com/privkey.pem"\n  }\n}',
+      },
       {
         method: 'POST',
         path: '/panel/api/nodes/add',