refactor: update to Rust 1.85 and edition 2024, use inline log args

- Update MSRV to 1.85 and Rust edition to 2024.
- Refactor all logging macros to use inline argument formatting.
- Fix import order in main.rs and examples.
- Add async environment variable setter to main.rs as safe facade.

examples/play_connect.rs

@@ -1,7 +1,7 @@
 use librespot::{
     connect::{ConnectConfig, LoadRequest, LoadRequestOptions, Spirc},
     core::{
-        authentication::Credentials, cache::Cache, config::SessionConfig, session::Session, Error,
+        Error, authentication::Credentials, cache::Cache, config::SessionConfig, session::Session,
     },
     playback::mixer::MixerConfig,
     playback::{