swap SDK submodule from open-x4 to freeink + add m5paper_v11 env

Adds driver support for the m5paper via the new freeink sdk

.gitmodules

@@ -1,3 +1,4 @@
-[submodule "open-x4-sdk"]
-	path = open-x4-sdk
-	url = https://github.com/crosspoint-reader/community-sdk.git
+[submodule "freeink-sdk"]
+	path = freeink-sdk
+	url = https://github.com/Free-Ink/freeink-sdk.git
+	branch = main

platformio.ini

@@ -55,47 +55,93 @@ extra_scripts =
   pre:scripts/patch_jpegdec.py
   post:scripts/register_unit_tests_target.py
 
-; Libraries
+; Libraries — FreeInk SDK (git submodule at ./freeink-sdk). The left-hand names
+; are the include paths the firmware already uses (<EInkDisplay.h>, etc.); FreeInk's
+; compat shim preserves them. BoardConfig + PowerManager are FreeInk-only and
+; required (device profiles + the SoC-correct deep-sleep wakeup the HAL relies on).
 lib_deps =
-  BatteryMonitor=symlink://open-x4-sdk/libs/hardware/BatteryMonitor
-  InputManager=symlink://open-x4-sdk/libs/hardware/InputManager
-  EInkDisplay=symlink://open-x4-sdk/libs/display/EInkDisplay
-  SDCardManager=symlink://open-x4-sdk/libs/hardware/SDCardManager
+  BatteryMonitor=symlink://freeink-sdk/libs/hardware/BatteryMonitor
+  InputManager=symlink://freeink-sdk/libs/hardware/InputManager
+  EInkDisplay=symlink://freeink-sdk/libs/display/FreeInkDisplay
+  SDCardManager=symlink://freeink-sdk/libs/hardware/SDCardManager
+  BoardConfig=symlink://freeink-sdk/libs/hardware/BoardConfig
+  PowerManager=symlink://freeink-sdk/libs/hardware/PowerManager
   bblanchon/ArduinoJson @ 7.4.2
   ricmoo/QRCode @ 0.0.1
   bitbank2/PNGdec @ 1.1.6
   https://github.com/bitbank2/JPEGDEC.git#86282979224c8a32fd51e091ed5a35b0c699a52b
   links2004/WebSockets @ 2.7.3
 
-[env:default]
+; ESP32-C3 device set: X3 + X4 compiled into one binary, runtime-selected after
+; the I2C fingerprint. FreeInk requires an explicit device selection, so the C3
+; envs extend this instead of [base] directly. (M5Paper is a different MCU family
+; and selects its own device below.)
+[c3]
 extends = base
 build_flags =
   ${base.build_flags}
+  -DFREEINK_DEVICE_X3=1
+  -DFREEINK_DEVICE_X4=1
+
+[env:default]
+extends = c3
+build_flags =
+  ${c3.build_flags}
   ; CROSSPOINT_VERSION is set by scripts/git_branch.py (includes branch + short SHA)
   -DENABLE_SERIAL_LOG
   -DLOG_LEVEL=2 ; Set log level to debug for development builds
 
 
 [env:gh_release]
-extends = base
+extends = c3
 build_flags =
-  ${base.build_flags}
+  ${c3.build_flags}
   -DCROSSPOINT_VERSION=\"${crosspoint.version}\"
   -DENABLE_SERIAL_LOG
   -DLOG_LEVEL=1 ; Set log level to info for release builds
 
 [env:gh_release_rc]
-extends = base
+extends = c3
 build_flags =
-  ${base.build_flags}
+  ${c3.build_flags}
   -DCROSSPOINT_VERSION=\"${crosspoint.version}-rc+${sysenv.CROSSPOINT_RC_HASH}\"
   -DENABLE_SERIAL_LOG
   -DLOG_LEVEL=1 ; Set log level to info for release candidate builds
 
 [env:slim]
-extends = base
+extends = c3
 build_flags =
-  ${base.build_flags}
+  ${c3.build_flags}
   -DCROSSPOINT_VERSION=\"${crosspoint.version}-slim\"
   ; serial output is disabled in slim builds to save space
   -UENABLE_SERIAL_LOG
+
+; --- M5Paper v1.1 (classic ESP32-D0WDQ6, 4.7" 540x960 / IT8951E) -------------
+; Different MCU family than the C3 base: override board/mcu/flash, disable the
+; C3-only native-USB CDC (logs over UART0), and select the M5Paper device.
+;   pio run -e m5paper_v11 -t upload --upload-port /dev/tty.usbserial-XXXX
+[env:m5paper_v11]
+extends = base
+board = esp32dev
+board_build.mcu = esp32
+board_build.flash_mode = qio
+; CP2104 bridge: 460800 is ~4x the 115200 fallback and reliable; drop if a flash
+; stalls. (921600 usually works too.)
+upload_speed = 460800
+build_flags =
+  ${base.build_flags}
+  -UARDUINO_USB_MODE
+  -UARDUINO_USB_CDC_ON_BOOT
+  -DBOARD_HAS_PSRAM
+  -DFREEINK_DEVICE_M5PAPER=1
+  ; git_branch.py only injects CROSSPOINT_VERSION for the default env; set it here.
+  -DCROSSPOINT_VERSION=\"${crosspoint.version}-m5paper_v11\"
+  -DENABLE_SERIAL_LOG
+  -DLOG_LEVEL=2
+  ; Touch + rotary: no physical button row, so hide on-screen button hints.
+  -DCROSSPOINT_SHOW_BUTTON_HINTS=0
+  ; Archive-order workarounds for the classic-ESP32 link (see freeink-sdk
+  ; platformio.crosspoint.sample.ini): force Arduino startup + the I2C HAL members.
+  -Wl,.pio/build/m5paper_v11/FrameworkArduino/main.cpp.o
+  -Wl,-u,i2cInit
+  -Wl,-u,i2cSlaveInit