[marcelverdult]

Cut E2a of step 11, as planned in docs/refactoring/0011-variant-target.md (section on cut E2 after upstream meshcore-dev#3753).

The GPS driver, the location provider and the sensor manager of 36 variants (shapes A and A') are now defined once in src/helpers/VariantTarget.cpp. Each of these variants drops the block from its target.cpp and gets one line #define SENSORS_TARGET_GLOBALS in its target.h. The type of sensors comes from target.h via decltype(sensors).

Diff: 36 target.cpp and 36 target.h, VariantTarget.cpp, plus 0011, README and the size table. 308 lines leave the target.cpp files (249 GPS block, 35 includes no longer needed, 24 blank lines).

Checks

• Builds before (3dd444a) and after, 128 environments of the 36 variants: 127 link in both trees. ThinkNode_M5_companion_radio_serial fails to compile in both trees (D6/D7 undeclared, set in variants/thinknode_m5/platformio.ini, which this PR does not touch). Station_G2_companion_radio_ble and Station_G3_ESP32_companion_radio_ble are 1.9 % over the flash partition in both trees alike.
• Sizes in docs/refactoring/cut-e2a-sizes-20261110.tsv: flash delta from -944 to +168 bytes, RAM delta 0 or 8 bytes.
• The cause of the flash delta was measured on Heltec_t114_repeater only (nm -S, -800 bytes): no symbol is added or removed, the linker keeps another copy of some inline functions. The +156 to +168 bytes on heltec_v4_tft_* were not measured separately.
• Init order: disassembly of Heltec_t114_repeater, Heltec_v3_repeater and one LilyGo_T-Echo_Card environment. The GPS driver's pin calls keep their order among themselves. The display and button constructors now run before them; according to the disassembly they write no pin.
• Host tests: 28 native environments, 2446 cases passed, 0 failed.

Not verified

• Behaviour on real hardware (pin state at boot, GPS fix).
• Init order of the variants that were not disassembled.
• lilygo_techo_card is part of the 36. Upstream T-Echo Card: switch GPS LNA with GPS power, enable L76K config meshcore-dev/MeshCore#3668 is open on that variant.