refactor: consume library crate from binary

main.rs declared its own module tree (mod bragi, cli, ...) while lib.rs
re-exported the same modules. The binary recompiled everything without
using the library, producing 9 spurious dead-code warnings for items
that are actually exercised by the integration tests via the library.

Import from the corsairctl library instead. No functional change;
eliminates all 9 warnings.

src/main.rs

@@ -1,16 +1,13 @@
 // ABOUTME: Einstiegspunkt für corsairctl — CLI-Dispatch zu Subcommands.
 // ABOUTME: Parst CLI-Argumente und delegiert an die jeweilige Funktionalität.
 
-mod bragi;
-mod cli;
-mod error;
-mod hid;
-mod output;
-mod sidetone;
-
 use clap::Parser;
 
-use cli::{Cli, Command};
+use corsairctl::bragi;
+use corsairctl::cli::{Cli, Command};
+use corsairctl::error;
+use corsairctl::output;
+use corsairctl::sidetone;
 
 fn run() -> error::Result<()> {
     let cli = Cli::parse();