style: crank clippy to pedantic+nursery and fix all lints

Enable the full clippy all + pedantic + nursery groups as workspace warnings,
with a small documented allow-list for the pedantic/nursery lints this project
intentionally does not follow (rustdoc-style requirements, deliberate numeric
casts in the protocol/UI layers, and a few noisy nursery lints). Also enable
the rust unused_lifetimes and unsafe_op_in_unsafe_fn lints.

Fixed every resulting warning (527 -> 0) mechanically per clippy's suggestions:
inline format args, const fns, item ordering, let-else, redundant clones,
map_or, cast_lossless, Eq derives, associated-fn conversions for methods that
never used self, and removing unnecessary Result wrappers whose call sites could
never propagate an error. No runtime behavior changed; cargo fmt applied.

cargo clippy --workspace --all-targets: 0 warnings. All tests pass.

soulseek-rs/src/main.rs

@@ -35,7 +35,7 @@ fn main() -> Result<()> {
     if let Some(log_file) = &cli.log_file {
         // SAFETY: Called before any threads are spawned
         unsafe {
-            env::set_var("LOG_FILE", log_file.to_string_lossy().to_string())
+            env::set_var("LOG_FILE", log_file.to_string_lossy().to_string());
         };
     }
 
@@ -76,17 +76,20 @@ fn main() -> Result<()> {
             search_and_download(config)
         }
         None => {
+            use ratatui::crossterm::{
+                event::EnableMouseCapture,
+                execute,
+                terminal::{Clear, ClearType},
+            };
+
             // Launch main TUI
             // Enable logger buffering BEFORE connection to prevent log artifacts
             soulseek_rs::utils::logger::enable_buffering();
 
             let settings = ClientSettings {
-                username: username.clone(),
-                password: password.clone(),
-                server_address: PeerAddress::new(
-                    server_host.clone(),
-                    server_port,
-                ),
+                username,
+                password,
+                server_address: PeerAddress::new(server_host, server_port),
                 enable_listen: !cli.disable_listener,
                 listen_port: cli.listener_port,
             };
@@ -102,11 +105,6 @@ fn main() -> Result<()> {
             let client = Arc::new(client);
 
             // Clear screen and enable mouse capture before initializing TUI
-            use ratatui::crossterm::{
-                event::EnableMouseCapture,
-                execute,
-                terminal::{Clear, ClearType},
-            };
             let _ = execute!(
                 std::io::stdout(),
                 Clear(ClearType::All),