sensecap solar: add poweroff/shutdown support and nrf52 PM parity

[Specter242]

Summary

Add SenseCAP Solar repeater power-management parity for software shutdown:

• Add board-level power management hooks for SenseCAP Solar (initiateShutdown, powerOff) with button-based wake/system-off behavior.
• Enable required SenseCAP Solar variant defines for NRF52 power-management.
• Add SenseCAP Solar LED/wiring parity updates:
  • update LoRa TX LED pin mapping (P_LORA_TX_LED) from 12 to 11 for board wiring parity,
  • explicitly switch LED_GREEN and LED_BLUE off in powerOff() before entering system-off.
• Add CLI aliases: poweroff and shutdown.
• Add stability/usability fixes for real device behavior:
  • configure wake button with pull-up in system-off to avoid floating/false wake,
  • add SenseCAP Solar repeater long-press user-button shutdown (hold ~1.5s).
• Update NRF52 power-management support docs matrix for SenseCAP Solar.

Why

SenseCAP Solar repeater firmware lacked a practical software power-off path and CLI shutdown command. This improves battery-device operability and aligns behavior with expected NRF52 power-management support.

Fixes #1872
Related to #1145

Validation

• ~/.local/bin/pio run -e SenseCap_Solar_repeater (SUCCESS)
• Verified firmware links and artifacts are produced for the target environment.

[willumpie82]

I checked out your firmware, thanks for implementing. (this is really helpfull when swapping e.g. the antenna

What I see that you changed the LED behaviour, and that the blue LED is always on goes off on 'poweroff", Is that intentionally? this will drain the battery of the node

[ripplebiz]

Can you change the base branch of this PR to 'dev' then I can merge.

[Specter242]

I'll take care of these in the next few days. I'm on a job right now.

[mvdbosch]

So how is this functionality supposed to work?

I am running v1.15.0 and I spend like 2 hours playing with the power button to get it to power down - so I can safely box the repeater for storage (and disconnect the antenna).

Expected behavior would be to press the button 3-10 secs. and the unit goes offline till the button is pressed again shortly.

[nwithan8]

So how is this functionality supposed to work?

I am running v1.15.0 and I spend like 2 hours playing with the power button to get it to power down - so I can safely box the repeater for storage (and disconnect the antenna).

Expected behavior would be to press the button 3-10 secs. and the unit goes offline till the button is pressed again shortly.

Hold the User button for 1.5 seconds: https://github.com/meshcore-dev/MeshCore/pull/1873/changes#diff-10a0092562d43e5bb73a25560e519d6106a0d09b143204ed36ae90d8a3ad24aaR136

[IoTThinks]

poweroff CLI will not work for most NRF52 repeaters.
We need to fix the powerOff() for many NRF52 repeaters.

powerOff CLI only works for SenseCap solar if NRF52 power management is enabled as it calls a custom code.

[IoTThinks]

This code is correct but not enough to power off for most NRF52 repeaters including SenseCap Solar repeater with NRF52 MANAGEMENT disabled.

This is because powerOff() for most NRF52 boards will call sd_power_system_off() which only valid for BLE companions.
NRF52 repeaters do not use softdevice.

By introducing "poweroff", the bug in current powerOff for NRF52 boards is accidentaly exposed.