[docs](trx-rs): record the trx-config crate and its commands

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SyX26FCpMQxiBoC7r5K1A7
Signed-off-by: Stan Grams <sjg@haxx.space>

CLAUDE.md

@@ -24,6 +24,12 @@ cargo test -p trx-core
 ./target/release/trx-server --print-config > trx-server.toml
 ./target/release/trx-client --print-config > trx-client.toml
 
+# Validate a config without starting anything (reports every problem)
+./target/release/trx-server --check-config --config trx-rs.toml
+
+# Regenerate trx-rs.toml.example after changing a config struct
+cargo run -p trx-config --example generate_example
+
 # Run server
 ./target/release/trx-server --config trx-server.toml
 # or via CLI args:
@@ -41,7 +47,8 @@ This is a Cargo workspace. All crates live under `src/`:
 src/
   trx-core/           # Core types, traits, state machine, controller (~3,500 LOC)
   trx-protocol/       # Client↔server protocol DTOs, auth, codec, mapping (~1,100 LOC)
-  trx-app/            # Shared application helpers (config paths, logging init)
+  trx-app/            # Shared application helpers (logging init, name normalization)
+  trx-config/         # Client + server config structs, loader, validators (~2,500 LOC)
   trx-reporting/      # PSKReporter UDP uplink + APRS-IS TCP uplink (~1,150 LOC)
   trx-server/         # Server binary: rig_task, audio pipeline, listener (~3,700 LOC)
     trx-backend/      # Backend abstraction trait + factory + dummy