fix: pre-scan WiFi before entering AP mode

wlan0 cannot scan while in AP mode (hardware limitation).
Now scan nearby networks before starting hotspot and cache
the results for the captive portal page.

Made-with: Cursor

lib/captive-server.js

@@ -2,7 +2,7 @@
 
 const http = require('http');
 const log  = require('./logger');
-const { scanWifi } = require('./network');
+// scanWifi 不再在此调用（AP 模式下无法扫描），改用缓存
 const { CAPTIVE_DOMAIN } = require('./dns-hijack');
 
 const PORT = 80;
@@ -30,9 +30,10 @@ const CAPTIVE_DETECT_PATHS = new Set([
  */
 class CaptiveServer {
   constructor(opts = {}) {
-    this._server    = null;
-    this._clawId    = opts.clawId || '???';
-    this._onConnect = opts.onConnect || null; // (ssid, password) => Promise<{success, error?}>
+    this._server        = null;
+    this._clawId        = opts.clawId || '???';
+    this._onConnect     = opts.onConnect || null;
+    this._cachedWifiList = opts.cachedWifiList || [];
   }
 
   startListening() {
@@ -96,8 +97,8 @@ class CaptiveServer {
   // ── API ──────────────────────────────────────────────────────────────────
 
   _apiScan(req, res) {
-    const list = scanWifi();
-    this._json(res, { wifi: list });
+    // AP 模式下 wlan0 无法扫描，返回开 AP 前的缓存结果
+    this._json(res, { wifi: this._cachedWifiList, cached: true });
   }
 
   async _apiConnect(req, res) {
@@ -227,7 +228,9 @@ async function doScan(){
       o.textContent=w.ssid+' ('+w.signal+'% '+w.security+')';
       sel.appendChild(o);
     });
-    setStatus('扫描到 '+d.wifi.length+' 个网络','ok');
+    var msg='发现 '+d.wifi.length+' 个网络';
+    if(d.wifi.length===0) msg='未发现网络，请手动输入 SSID';
+    setStatus(msg,'ok');
   }catch(e){setStatus('扫描失败: '+e.message,'err')}
   $('connectBtn').disabled=false;
 }