Simplify client proxy port handling

src/server/config.js

@@ -1,14 +1,27 @@
 import path from "node:path";
 
 const dataDir = process.env.DATA_DIR || path.resolve(".vpn-proxy");
+const parsePort = (value, fallback) => {
+  const parsed = Number.parseInt(value, 10);
+  return Number.isInteger(parsed) ? parsed : fallback;
+};
+const proxyPort = parsePort(process.env.PROXY_PORT, 8080);
+const clientProxyPortStart = parsePort(
+  process.env.CLIENT_PROXY_PORT_START,
+  proxyPort,
+);
+const clientProxyPortEnd = parsePort(
+  process.env.CLIENT_PROXY_PORT_END,
+  clientProxyPortStart,
+);
 
 export const settings = {
   appMode: process.env.APP_MODE === "client" ? "client" : "gateway",
-  port: Number(process.env.PORT || 3456),
-  proxyPort: Number(process.env.PROXY_PORT || 8080),
-  clientProxyPortStart: Number(process.env.CLIENT_PROXY_PORT_START || 8080),
-  clientProxyPortEnd: Number(process.env.CLIENT_PROXY_PORT_END || 8090),
-  tproxyPort: Number(process.env.TPROXY_PORT || 7895),
+  port: parsePort(process.env.PORT, 3456),
+  proxyPort,
+  clientProxyPortStart,
+  clientProxyPortEnd,
+  tproxyPort: parsePort(process.env.TPROXY_PORT, 7895),
   tproxyChain: process.env.TPROXY_CHAIN || "VPN_PROXY_TPROXY",
   tproxySourceBypassChain:
     process.env.TPROXY_SOURCE_BYPASS_CHAIN || "VPN_PROXY_SRC_BYPASS",

src/server/singbox.js

@@ -347,7 +347,7 @@ export function buildGatewayConfig(
             includeTransparent: !clientMode,
           }),
       final: "direct",
-      auto_detect_interface: true,
+      ...(clientMode ? {} : { auto_detect_interface: true }),
     },
   };
 }

src/web/components/ClientOverviewPage.jsx

@@ -203,6 +203,7 @@ function ProxySettings({ state, settings, busy, onSave }) {
   const parsed = Number.parseInt(draftPort, 10);
   const invalid = !Number.isInteger(parsed) || parsed < range.start || parsed > range.end;
   const dirty = !invalid && parsed !== port;
+  const singlePublishedPort = range.start === range.end;
 
   return (
     <aside className="client-side-panel">
@@ -222,17 +223,20 @@ function ProxySettings({ state, settings, busy, onSave }) {
             min={range.start}
             max={range.end}
             value={draftPort}
+            disabled={singlePublishedPort}
             onChange={(e) => setDraftPort(e.target.value)}
           />
           <button
             className="btn btn-secondary"
-            disabled={busy || !dirty}
+            disabled={busy || singlePublishedPort || !dirty}
             onClick={() => onSave({ ...settings, proxyPort: parsed })}
           >
             Save
           </button>
         </div>
-        <small className={invalid ? 'field-error' : 'field-hint'}>{range.start}–{range.end}</small>
+        <small className={invalid ? 'field-error' : 'field-hint'}>
+          {singlePublishedPort ? 'Порт задаётся установщиком' : `${range.start}–${range.end}`}
+        </small>
       </div>
     </aside>
   );