Portal customization API v2, SPA hardening, and test cleanup

- Group portal state into brand/pages/actions/layout structs; portal* API
- Bootstrap JSON: nested brand/context/pages/actions/layout; param kind
- Handlers: PROGMEM default CSS when no override/append; dynamic CSS path
- PortalAppJS: portal timeout countdown; safe WiFi scan DOM; serialized
  scan-status polling; fetch error handling; wm:view-changed on redirects
- CSS: scan list icon alignment; wm-status for timeout
- Tests: remove low-value/no-op tests; trim fragile JS substring checks

test/test_wifimanager/tests/test_basic.cpp

@@ -9,10 +9,7 @@ void test_basic_wifimanager_instantiation() {
     
     // Test default constructor
     WiFiManager wm;
-    
-    // Verify instance created (basic sanity check)
-    TEST_ASSERT_TRUE_MESSAGE(true, "WiFiManager instance created successfully");
-    
+
     // Test that we can call basic methods without crashing
     String defaultName = wm.getDefaultAPName();
     TEST_ASSERT_GREATER_THAN(0, defaultName.length());
@@ -69,9 +66,6 @@ void test_disconnect() {
     // Can be called multiple times safely
     (void)wm.disconnect();
     
-    // Verify no crash (results may be true/false depending on WiFi state)
-    TEST_ASSERT_TRUE_MESSAGE(true, "disconnect() executed without crash");
-    
     Serial.println("[TEST]   disconnect() test completed successfully");
 }