Keep every screen's Wi-Fi awake from the shared core, so Home Assistant's messages no longer wait for the router's next beacon (0.2.88)

packages/core.yaml sets wifi: power_save_mode: none. ESPHome merges it
under the screen's own wifi: block, which keeps the network, the password
and the hotspot, and the screen's own YAML still wins on the mode. The
YAML ESP Screens writes has had the line since app 0.2.24; screens with
an older or hand-written YAML ran ESPHome's ESP32 default light, and
their messages from Home Assistant waited 76-117 ms on the bench.

esphome config on the bench screens' Device Builder YAMLs: NONE for both
without a line of their own, LIGHT when the YAML says light. The bench
Guition, flashed from its Device Builder YAML: ping 15 ms average instead
of 117 ms. tools/check.sh: 474 Python tests (a new one keeps the core's
wifi: block to this one key), 19/19 C++, editor; firmware unchanged in
size (CYD 1,678,816 B, 91.5 %; Guition 2,055,280 B), since the checkout
profiles already had the line.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

packages/boards/guition-4848s040.yaml

@@ -372,9 +372,9 @@ api:
 # Camera images (firmware 0.2.57+): ESP Screen Manager serves each image already sized for this screen, as an uncompressed
 # BMP on its own port on the LAN (screen_manager/app/camera_feed.py). ESPHome decodes a BMP piece by piece as it arrives,
 # one `buffer_size` per loop, where a JPEG of the full screen held the loop for 0.6 s; touch and drawing keep their turn.
-# 16 KB a loop (firmware 0.2.73+): the full picture came in 1.8 s instead of 2.8 s with 4 KB. Without Wi-Fi power save no
-# loop waited over 50 ms for it (with power save now and then 0.1 s, against 65 ms with 4 KB); 32 KB saved 0.3 s more but
-# held a loop 0.1 s even without power save (docs/TEST_RESULTS_0287.md). One image full screen and one in an alert's
+# 16 KB a loop (firmware 0.2.73+): the full picture came in 1.8 s instead of 2.8 s with 4 KB. A loop waited over 50 ms
+# for it in one of eleven opens with Wi-Fi awake (0.1 s), in five of twelve with power save; 32 KB saved 0.3 s more but
+# held a loop 0.1 s more often (docs/TEST_RESULTS_0287.md, 0288). One image full screen and one in an alert's
 # frame; runtime_tiles.h decides when they load and frees them when they close. Plain HTTP on the LAN, no certificates.
 http_request:
   timeout: 4s

packages/core.yaml

@@ -14,7 +14,7 @@
 # fonts/materialdesignicons-webfont.ttf (Apache 2.0, github.com/Templarian/MaterialDesign-Webfont).
 ############################################################
 substitutions:
-  SCREEN_FIRMWARE_VERSION: "0.2.73"
+  SCREEN_FIRMWARE_VERSION: "0.2.74"
   DASHBOARD_INBOX_INTERNAL: "false"
   CALIBRATION_ON_BOOT: "false"                     # a bench build: start on the touch test page
   ROOM_NAME: ""                                    # top left until ESP Screens sends the screen name
@@ -261,6 +261,13 @@ logger:
     homeassistant.sensor: WARN
     homeassistant.text_sensor: WARN
 
+# A screen hangs on the mains, so its Wi-Fi never dozes (firmware 0.2.74+). With ESPHome's default for the ESP32,
+# `light`, every message from Home Assistant waits at the router for the next beacon: 76-117 ms on the bench screens
+# against about 20 ms, and an image download held a loop up to 0.1 s now and then (docs/TEST_RESULTS_0287.md). The
+# network and its password stay in the screen's own YAML, and a `power_save_mode` there wins over this one.
+wifi:
+  power_save_mode: none
+
 
 # Credentials are loaded from secrets.yaml — copy secrets.yaml.example to secrets.yaml and fill in your values.
 api: