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>

docs/RELEASING.md

@@ -219,6 +219,16 @@ icons sit off-center in the browser).
 The `MDI_GLYPH_*` substitutions are retired: `TILEn_ICON` in manual
 profiles must come from the set. No changed preferences or keys.
 
+### Compatibility 0.2.88 / firmware 0.2.74
+
+Firmware only, one setting: `packages/core.yaml` has `wifi: power_save_mode: none`, the first `wifi:` key in a package.
+ESPHome merges it under the screen's own `wifi:` block, which keeps the network, the password and the fallback hotspot,
+and the screen's own YAML wins on the mode as on any key (`merge_config`: the main config over every package). The
+YAML ESP Screens writes has had the same line since app 0.2.24; screens with an older or hand-written YAML ran ESPHome's
+ESP32 default `light` (`WIFI_PS_MIN_MODEM`). The app's Override YAML still refuses `wifi:` (`PROTECTED_OVERRIDE_KEYS`).
+No protocol, storage, preference or key change. `tests/test_easy_package.py` keeps the core's `wifi:` block to that one
+key and every other package without one. Details: docs/TEST_RESULTS_0288.md.
+
 ### Compatibility 0.2.87 / firmware 0.2.73
 
 Firmware only, plus README pictures and docs/CAMERA.md. No protocol, storage, preference or key change: an older app
@@ -235,7 +245,7 @@ drives this firmware as before, and the camera messages are the same; only when
   4 s refresh and the retries. `camera_spinner` turns until the first picture or a note; its ring is the new theme
   role `CAMERA_TRACK` (0x393D42 in both looks). "Loading image" is gone.
 - Guition `online_image` `buffer_size` 16384 (was 4096) for `camera_image` and `alert_image`: the full picture in
-  about 1.8 s instead of 2.8 s on the bench; without Wi-Fi power save no loop over 50 ms. 32 KB held a loop 0.1 s.
+  about 1.8 s instead of 2.8 s on the bench; a loop over 50 ms is rare with Wi-Fi awake. 32 KB held a loop 0.1 s.
 - Alert picture: `alert_image_frame` has the alert card's radius (18) and `camera_show()` gives the alert's picture the
   frame's radius. LVGL 9.5 clips an image to its own radius row by row (`radius_only` in `lv_draw_sw_img.c`) without a
   layer, so `clip_corner` stays out (`tests/test_layer_free.py`). About 5 % more render time for the picture on the