fix: define NFC-A destructors out of line

[Sped0n]

Problem

NFCLayerA owns a std::unique_ptr<Adapter>, but Adapter is only forward-declared when the compiler sees the implicit inline destructor for NFCLayerA.

This can trigger incomplete-type diagnostics in clangd:

In included file: invalid application of 'sizeof' to an incomplete type 'm5::nfc::NFCLayerA::Adapter' [sizeof_alignof_incomplete_or_sizeless_type]
unique_ptr.h:91:16: Error occurred here
unique_ptr.h:398:4: In instantiation of member function 'std::default_delete<m5::nfc::NFCLayerA::Adapter>::operator()' requested here
nfc_layer_a.hpp:43:7: In instantiation of member function 'std::unique_ptr<m5::nfc::NFCLayerA::Adapter>::~unique_ptr' requested here
nfc_layer_a.hpp:43:7: In implicit destructor for 'm5::nfc::NFCLayerA' first required here
nfc_layer_a.hpp:45:12: Forward declaration of 'm5::nfc::NFCLayerA::Adapter'

The same ownership pattern exists in EmulationLayerA.

Change Overview

• Declare destructors for NFCLayerA and EmulationLayerA in their headers.
• Define both destructors out-of-line in their .cpp files.

Testing

Tested on CoreS3 with Unit NFC: platformio test -e test_UnitNFC_CoreS3 --upload-port /dev/ttyACM0 --test-port /dev/ttyACM0, 145/145 test cases passed.