Shared e-ink hardware layer: foundation for target-by-target migration off GxEPD2 (#11142)

* Add shared e-ink hardware layer (graphics/eink) alongside legacy drivers

Foundation for a target-by-target migration off the GxEPD2-based
EInkDisplay2/EInkDynamicDisplay/EInkParallelDisplay stack:

- src/graphics/eink/: chipset drivers, panel profiles, backlight helper
  (promoted from the InkHUD driver set, shared by BaseUI and InkHUD)
- src/graphics/BaseUIEInkDisplay: OLEDDisplay adapter driving the new
  layer, with EINK_* compat macros matching EInkDynamicDisplay
- [niche] build helper in platformio.ini; graphics/eink/ excluded from
  arduino_base so unconverted targets are unaffected
- Screen/CannedMessageModule dispatch between the two stacks per env
- InkHUD-specific touch code in TouchScreenImpl1 guarded with
  MESHTASTIC_INCLUDE_INKHUD (no-op today, required once BaseUI variants
  define MESHTASTIC_INCLUDE_NICHE_GRAPHICS without InkHUD)

No variant is converted and no legacy file is removed; every existing
env builds identical firmware.

* Fix clang-format comment alignment in Screen.cpp

* Address review findings in the e-ink driver layer

- Screen.cpp: exclude InkHUD builds from all NicheGraphics BaseUI guards
- BaseUIEInkDisplay: size the OLEDDisplay buffer from its actual indexing
- EInkParallel: defer update() while an async refresh is in flight, honor
  the selected clear mode in the async task, never delete a live task
- ED047TC1: clean up on failed initPanel, fix inverted bbepI2CWrite checks
- UC8175: drop bogus 0x12 soft reset (0x12 is display refresh on UC8175)
- LCMEN2R13EFC1: guard absent reset pin, bound the busy wait
- SSD16XX/SSD1682: build the RAM window from the instance, not statics
- Doc corrections in driver banners and Drivers/README

* SSD16XX/SSD1682: send inclusive Y-end address (height - 1)

* LCMEN213EFC1: adopt the shared wait timeout / fail-through pattern

wait() now bounds the busy poll via Throttle and sets the EInk failed
flag on timeout; sendCommand/sendData fail through like the SSD16XX and
UC8175 drivers. EInk::runOnce clears the flag after the failed cycle.

platformio.ini

@@ -12,6 +12,15 @@ extra_configs =
 
 description = Meshtastic
 
+; Shared E-Ink hardware layer (chipset drivers, panel profiles, backlight).
+; Variants opt in by extending this env; unconverted variants keep the legacy
+; EInkDisplay2/EInkDynamicDisplay stack. See src/graphics/eink/.
+[niche]
+build_src_filter =
+  +<graphics/eink/>
+build_flags =
+  -D MESHTASTIC_INCLUDE_NICHE_GRAPHICS
+
 [env]
 test_build_src = true
 extra_scripts =
@@ -104,7 +113,7 @@ build_unflags =
 	-std=gnu++11
 build_flags = ${env.build_flags} -Os
 	-std=gnu++17
-build_src_filter = ${env.build_src_filter} -<platform/> +<platform/extra_variants/> -<graphics/niche/>
+build_src_filter = ${env.build_src_filter} -<platform/> +<platform/extra_variants/> -<graphics/niche/> -<graphics/eink/>
 
 ; Common libs for communicating over TCP/IP networks such as MQTT
 [networking_base]