fix(build): disable tracing default features, cap at debug level

Drop tracing-attributes proc macro (no #[instrument] usage) and
compile out trace!() calls via release_max_level_debug. Debug level
remains available for --debug flag. Saves ~254KB in slim binary,
bringing it back under 5MiB.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: maxholman

Cargo.toml

@@ -11,7 +11,7 @@ pedantic = "warn"
 [workspace.dependencies]
 arc-swap = "1"
 tokio = { version = "1.0" }
-tracing = "0.1"
+tracing = { version = "0.1", default-features = false, features = ["std", "release_max_level_debug"] }
 thiserror = "2"
 console-subscriber = "0.4"
 parking_lot = "0.12"