ci: add current ESP32 validation lane

platformio.ini

@@ -3,6 +3,8 @@
 ; Full suite:
 ;   pio test -e esp8266
 ;   pio test -e esp32
+;   ./scripts/test.sh compile --platform esp32_3_3_11
+;     (uses the isolated current Arduino-ESP32 validation lane)
 ;
 ; Single suite (examples):
 ;   pio test -e esp8266 --filter test_utils_serializers
@@ -30,6 +32,10 @@ extends = common
 test_ignore = test_native_core
 platform = espressif8266
 board = d1_mini
+; Keep root Unity coverage on the same Postmortem relocation-fix snapshot as
+; the maintained ESP8266 examples. See docs/ESP8266-LINKER-WORKAROUND.md.
+platform_packages =
+    platformio/framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git#521ae60a89e64bb0d1eb7a0b7addf620ced5cad3
 
 [env:esp32]
 extends = common
@@ -39,6 +45,12 @@ board = esp32dev
 build_unflags = -std=gnu++11
 build_flags = ${common.build_flags} -std=gnu++14
 
+; Current Arduino-ESP32 validation lane. Keep the legacy env above until the
+; supported floor changes through an explicit compatibility decision.
+[env:esp32_3_3_11]
+extends = env:esp32
+platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.311/platform-espressif32.zip
+
 ; Host-only regression checks for serialization, topic validation, and the
 ; PubSubClient mock path. The Arduino compatibility files live exclusively
 ; under test/native and are never included in firmware environments.