Fix async WiFi scanning and captive portal redirects

- Fix captive portal redirect to preserve URL path and query params
- Fix password field rendering for WiFi networks (encryption detection)
- Add WiFiPollingJS template for AJAX polling (currently disabled due to size limit)
- Remove blocking WiFi scan operations
- Add debug output for response handling

lib/WiFiManager/include/templates/WiFiPollingJS.h

@@ -66,12 +66,17 @@ function updateNetworkList(data) {
   } else if(data.networks && data.networks.length > 0) {
     data.networks.forEach(function(network) {
       let qualityPercent = network.quality + '%';
-      let encrypted = network.enc_type !== 0 ? '<span class="l">🔒</span>' : '';
+      // Map quality 0-100 to icon level 1-4
+      let qualityIcon = Math.round((network.quality / 100) * 3) + 1;
+      if(qualityIcon < 1) qualityIcon = 1;
+      if(qualityIcon > 4) qualityIcon = 4;
+      // Encryption class: 'l' if encrypted, empty if open
+      let encClass = network.enc_type !== 0 ? 'l' : '';
       let ssidEscaped = escapeHtml(network.ssid);
+      // Match original template structure: icon div with quality + encryption class, then percentage div
       html += '<div><a href="#p" onclick="c(this)" data-ssid="' + ssidEscaped + '">' + ssidEscaped + '</a>';
-      html += '<div role="img" aria-label="' + qualityPercent + '" title="' + qualityPercent + '" class="q q-' + network.quality + '"></div>';
+      html += '<div role="img" aria-label="' + qualityPercent + '" title="' + qualityPercent + '" class="q q-' + qualityIcon + ' ' + encClass + '"></div>';
       html += '<div class="q">' + qualityPercent + '</div>';
-      html += encrypted;
       html += '</div>';
     });
   }

lib/WiFiManager/include/wm_strings_en.h

@@ -31,10 +31,13 @@ const char HTTP_HEAD_START[]       PROGMEM = "<!DOCTYPE html>"
 
 const char HTTP_SCRIPT[]           PROGMEM = "<script>function c(l){"
 "document.getElementById('s').value=l.getAttribute('data-ssid')||l.innerText||l.textContent;"
-"p = l.nextElementSibling.classList.contains('l');"
-"document.getElementById('p').disabled = !p;"
-"if(p)document.getElementById('p').focus();};"
+"var parent = l.parentElement;"
+"var isEncrypted = parent.querySelector('.l') !== null || (l.nextElementSibling && l.nextElementSibling.classList.contains('l'));"
+"var pField = document.getElementById('p');"
+"if(isEncrypted){pField.removeAttribute('disabled');pField.focus();}else{pField.setAttribute('disabled','');};"
+"};"
 "function f() {var x = document.getElementById('p');x.type==='password'?x.type='text':x.type='password';}"
+"window.addEventListener('load',function(){var pField = document.getElementById('p');pField.removeAttribute('disabled');});"
 "</script>"; // @todo add button states, disable on click , show ack , spinner etc
 
 const char HTTP_HEAD_END[]         PROGMEM = "</head><body class='{c}'><div class='wrap'>"; // {c} = _bodyclass

lib/WiFiManager/src/WiFiManager.cpp

@@ -1382,7 +1382,14 @@ void WiFiManager::handleRoot(AsyncWebServerRequest *request) {
 void WiFiManager::handleWifi(AsyncWebServerRequest *request, boolean scan) {
   #ifdef WM_DEBUG_LEVEL
   DEBUG_WM(WM_DEBUG_VERBOSE, F("<- HTTP Wifi"));
+  DEBUG_WM(WM_DEBUG_DEV, F("handleWifi called, scan="), scan ? "true" : "false");
   #endif
+  if (captivePortal(request)) {
+    #ifdef WM_DEBUG_LEVEL
+    DEBUG_WM(WM_DEBUG_DEV, F("Captive portal redirect"));
+    #endif
+    return; // If captive portal redirect instead of displaying the page
+  }
   handleRequest(request);
   String page = getHTTPHead(FPSTR(S_titlewifi), FPSTR(C_wifi)); // @token titlewifi
   if (scan) {
@@ -1441,15 +1448,29 @@ void WiFiManager::handleWifi(AsyncWebServerRequest *request, boolean scan) {
   if(_showBack) page += FPSTR(HTTP_BACKBTN);
   reportStatus(page);
   
-  // Add JavaScript for AJAX polling
-  page += FPSTR(WIFI_POLLING_JS);
+  // TODO: Known issue - Adding WIFI_POLLING_JS causes silent failure (empty response)
+  // This is likely due to:
+  // 1. String size limit: Page is already ~9-10KB, adding ~2.5KB JS may exceed ESPAsyncWebServer limits
+  // 2. Memory fragmentation: Large String append operations on ESP8266 can cause heap fragmentation
+  // 3. PROGMEM access: FPSTR() on large PROGMEM strings may have timing issues with async operations
+  // 4. Response size: ESPAsyncWebServer may silently fail or truncate responses exceeding ~12KB
+  // Workaround: Temporarily disabled until we can optimize the page size or use chunked responses
+  // page += FPSTR(WIFI_POLLING_JS);
   
   page += getHTTPEnd();
 
+  #ifdef WM_DEBUG_LEVEL
+  DEBUG_WM(WM_DEBUG_DEV, F("Page length: "), String(page.length()));
+  DEBUG_WM(WM_DEBUG_DEV, F("_numNetworks: "), String(_numNetworks));
+  DEBUG_WM(WM_DEBUG_DEV, F("_scanInProgress: "), _scanInProgress ? "true" : "false");
+  DEBUG_WM(WM_DEBUG_DEV, F("_lastscan: "), String(_lastscan));
+  DEBUG_WM(WM_DEBUG_DEV, F("About to send response"));
+  #endif
+
   request->send(200, FPSTR(HTTP_HEAD_CT), page);
 
   #ifdef WM_DEBUG_LEVEL
-  DEBUG_WM(WM_DEBUG_DEV, F("Sent config page"));
+  DEBUG_WM(WM_DEBUG_DEV, F("Response sent"));
   #endif
 }
 
@@ -2638,8 +2659,21 @@ boolean WiFiManager::captivePortal(AsyncWebServerRequest *request) {
     #ifdef WM_DEBUG_LEVEL
     DEBUG_WM(WM_DEBUG_VERBOSE, F("<- Request redirected to captive portal"));
     DEBUG_WM(WM_DEBUG_DEV, "serverLoc " + serverLoc);
+    DEBUG_WM(WM_DEBUG_DEV, "Original URL " + request->url());
     #endif
-    request->redirect((String)F("http://") + serverLoc);
+    // Preserve the original path in the redirect
+    String redirectUrl = (String)F("http://") + serverLoc + request->url();
+    if (request->params() > 0) {
+      redirectUrl += F("?");
+      for (size_t i = 0; i < request->params(); i++) {
+        if (i > 0) redirectUrl += F("&");
+        redirectUrl += request->getParam(i)->name() + F("=") + request->getParam(i)->value();
+      }
+    }
+    #ifdef WM_DEBUG_LEVEL
+    DEBUG_WM(WM_DEBUG_DEV, "Redirect URL " + redirectUrl);
+    #endif
+    request->redirect(redirectUrl);
     return true;
   }
   return false;