[feat](trx-rs): add marine mode scaffolding and VDES fallback

Keep weak VDES bursts visible by emitting unsynced diagnostic frames instead of dropping them, remove receiver badges from FT8 and WSPR history rows, and carry the current MARINE composite-mode scaffolding through the shared mode enums and backend mappings.

Co-authored-by: OpenAI Codex <codex@openai.com>
Signed-off-by: Stanislaw Grams <stanislawgrams@gmail.com>

src/trx-protocol/src/codec.rs

@@ -24,6 +24,7 @@ pub fn parse_mode(s: &str) -> RigMode {
         "WFM" => RigMode::WFM,
         "AIS" => RigMode::AIS,
         "VDES" => RigMode::VDES,
+        "MARINE" => RigMode::MARINE,
         "DIG" | "DIGI" => RigMode::DIG,
         "PKT" | "PACKET" => RigMode::PKT,
         other => RigMode::Other(other.to_string()),
@@ -45,6 +46,7 @@ pub fn mode_to_string(mode: &RigMode) -> String {
         RigMode::WFM => "WFM".to_string(),
         RigMode::AIS => "AIS".to_string(),
         RigMode::VDES => "VDES".to_string(),
+        RigMode::MARINE => "MARINE".to_string(),
         RigMode::DIG => "DIG".to_string(),
         RigMode::PKT => "PKT".to_string(),
         RigMode::Other(s) => s.clone(),