refactor: split into independent trx-server and trx-client binaries

Delete trx-bin (all-in-one) and trx-bin-common (shared lib). Each binary
now has its own config, plugins, and helper modules inlined.

- trx-server: backend-only daemon with ServerConfig (general, rig, behavior)
  no frontend dependencies
- trx-client: remote client with ClientConfig (general, remote, frontends)
  includes all frontend support (http, rigctl, http-json, qt)
- Dedicated config files: trx-server.toml / trx-client.toml

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

Cargo.toml

@@ -4,7 +4,8 @@
 
 [workspace]
 members = [
-    "src/trx-bin",
+    "src/trx-server",
+    "src/trx-client",
     "src/trx-backend",
     "src/trx-backend/src/trx-backend-ft817",
     "src/trx-core",