[feat](trx-config): report unknown configuration keys

Every config struct is #[serde(default)], so a misspelled key was dropped in
silence and the setting kept its default.  Writing `prot = 9999` under
[listen] started the server on 4530 without a word.

Collect the ignored key paths with serde_ignored and pair each with the
closest known key at the same level:

    WARN unknown config key 'listen.prot' (did you mean 'listen.port'?)

Warnings by default, so a config written for a newer version still runs on an
older binary; --strict-config makes them fatal for CI.  Logging now starts
before validation so these warnings are actually visible.

trx-configurator --check drops its hand-maintained key lists and re-implemented
range checks in favour of the real loader and validators, so it no longer
passes configs the binaries reject.

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>

src/trx-configurator/Cargo.toml

@@ -15,6 +15,7 @@ path = "src/main.rs"
 clap = { workspace = true, features = ["derive"] }
 dialoguer = "0.11"
 tokio-serial = { workspace = true }
+toml = "0.8"
 toml_edit = "0.22"
 trx-config = { path = "../trx-config" }