FT2 decoder implementation, protocol constants, server decoder tasks,
background decode, and registry entry are now conditional on the ft2
feature. Lightweight types (enum variants, commands, state fields) remain
unconditional to avoid cascading cfg noise in macros and serde.
Enable with: cargo build -p trx-server --features ft2
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
sjg
316d624c95
