[fix](trx-rs): use per-message rig_id for map marker tagging

The map module was tagging all decode markers (APRS, AIS, VDES,
FT8/FT4/FT2/WSPR locators) with the global rig picker's active rig
instead of the actual source rig. This made the map's own rig filter
dropdown ineffective in multi-rig setups.

- Add rig_id field to all decode message structs (AisMessage,
  VdesMessage, AprsPacket, CwEvent, Ft8Message, WsprMessage)
- Set rig_id on messages in audio_client before broadcasting, using
  the actual rig connection identifier
- Update history collector to prefer message rig_id over the global
  active rig fallback
- Pass rig_id through plugin normalize functions (AIS, APRS, VDES,
  HF-APRS) so it reaches the map add functions
- Update all map marker functions (aprsMapAddStation, aisMapAddVessel,
  vdesMapAddPoint, mapAddLocator) to use the message's rig_id with
  fallback to the global picker for backward compatibility

https://claude.ai/code/session_015gC7axHk2jmp7HbFPdbivN
Signed-off-by: Claude <noreply@anthropic.com>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/plugins/ais.js

@@ -326,6 +326,7 @@ function addAisMessage(msg) {
 
 function normalizeServerAisMessage(msg) {
   return {
+    rig_id: msg.rig_id || null,
     channel: msg.channel,
     message_type: msg.message_type,
     mmsi: msg.mmsi,