[refactor](decoders): consolidate decoder crates under src/decoders/

Move trx-ft8 and trx-wspr into src/decoders/ alongside a new trx-aprs
crate that extracts the Bell 202/AX.25 decoder from trx-server, giving
all three modems a consistent crate-per-decoder layout.

- src/decoders/trx-ft8/  (moved from src/trx-ft8/)
- src/decoders/trx-wspr/ (moved from src/trx-wspr/)
- src/decoders/trx-aprs/ (new — Bell 202 AFSK + AX.25/APRS decoder)
- trx-ft8/build.rs: fix external/ft8_lib relative path after move
- trx-server: drop decode::aprs module, use trx_aprs::AprsDecoder
- AprsPacket stays in trx-core (mirrors Ft8Message / WsprMessage)
- Workspace Cargo.toml updated with new member paths

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/decoders/trx-aprs/Cargo.toml

@@ -0,0 +1,11 @@
+# SPDX-FileCopyrightText: 2026 Stanislaw Grams <stanislawgrams@gmail.com>
+#
+# SPDX-License-Identifier: BSD-2-Clause
+
+[package]
+name = "trx-aprs"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+trx-core = { path = "../../trx-core" }

src/decoders/trx-aprs/src/lib.rs

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2025 Stanislaw Grams <stanislawgrams@gmail.com>
+// SPDX-FileCopyrightText: 2026 Stanislaw Grams <stanislawgrams@gmail.com>
 //
 // SPDX-License-Identifier: BSD-2-Clause
 

src/decoders/trx-ft8/build.rs

@@ -3,7 +3,7 @@
 // SPDX-License-Identifier: BSD-2-Clause
 
 fn main() {
-    let base = "../../external/ft8_lib";
+    let base = "../../../external/ft8_lib";
     let mut build = cc::Build::new();
     build
         .include(base)

src/trx-server/Cargo.toml

@@ -24,6 +24,7 @@ opus = "0.3"
 trx-app = { path = "../trx-app" }
 trx-backend = { path = "trx-backend" }
 trx-core = { path = "../trx-core" }
-trx-ft8 = { path = "../trx-ft8" }
-trx-wspr = { path = "../trx-wspr" }
+trx-aprs = { path = "../decoders/trx-aprs" }
+trx-ft8 = { path = "../decoders/trx-ft8" }
+trx-wspr = { path = "../decoders/trx-wspr" }
 trx-protocol = { path = "../trx-protocol" }

src/trx-server/src/audio.rs

@@ -22,6 +22,7 @@ use trx_core::audio::{
 };
 use trx_core::decode::{AprsPacket, DecodedMessage, Ft8Message, WsprMessage};
 use trx_core::rig::state::{RigMode, RigState};
+use trx_aprs::AprsDecoder;
 use trx_ft8::Ft8Decoder;
 use trx_wspr::WsprDecoder;
 
@@ -666,7 +667,7 @@ pub async fn run_aprs_decoder(
     decode_logs: Option<Arc<DecoderLoggers>>,
 ) {
     info!("APRS decoder started ({}Hz, {} ch)", sample_rate, channels);
-    let mut decoder = decode::aprs::AprsDecoder::new(sample_rate);
+    let mut decoder = AprsDecoder::new(sample_rate);
     let mut was_active = false;
     let mut last_reset_seq: u64 = 0;
     let mut active = matches!(state_rx.borrow().status.mode, RigMode::PKT);

src/trx-server/src/decode/mod.rs

@@ -2,5 +2,4 @@
 //
 // SPDX-License-Identifier: BSD-2-Clause
 
-pub mod aprs;
 pub mod cw;