style: Apply rustfmt with stable-only config

- Fixed rustfmt.toml to only use stable options (removed nightly-only)
- Applied cargo fmt --all to fix formatting violations
- Stable options: edition=2021, max_width=100, reorder_imports/modules, match_block_trailing_comma

crates/pm-core/src/logging.rs

@@ -1,5 +1,5 @@
-use tracing_subscriber::{fmt, layer::SubscriberExt, util::SubscriberInitExt, EnvFilter};
 use crate::config::LoggingConfig;
+use tracing_subscriber::{fmt, layer::SubscriberExt, util::SubscriberInitExt, EnvFilter};
 
 /// Initialize the global tracing subscriber.
 ///
@@ -10,8 +10,7 @@ use crate::config::LoggingConfig;
 /// Log level is controlled by `cfg.level` (e.g. `"info"`, `"debug"`).
 /// The `RUST_LOG` environment variable overrides `cfg.level`.
 pub fn init(cfg: &LoggingConfig) {
-    let filter = EnvFilter::try_from_default_env()
-        .unwrap_or_else(|_| EnvFilter::new(&cfg.level));
+    let filter = EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new(&cfg.level));
 
     match cfg.format.as_str() {
         "json" => {
@@ -19,13 +18,13 @@ pub fn init(cfg: &LoggingConfig) {
                 .with(filter)
                 .with(fmt::layer().json().with_current_span(true))
                 .init();
-        }
+        },
         _ => {
             tracing_subscriber::registry()
                 .with(filter)
                 .with(fmt::layer().pretty())
                 .init();
-        }
+        },
     }
 
     tracing::info!(format = %cfg.format, level = %cfg.level, "Logging initialized");