chore(lint): clean up clippy warnings across workspace

Auto-applied cargo clippy --fix across 11 files — needless return,
unnecessary cast, map_or simplification, repeat().take() → repeat_n(),
iter().any() → contains(), manual char comparison, lifetime elision,
push_str single-char, reference immediately dereferenced.

Also fixed three lints on file_storage.rs manually: two doc-list-item
overindentations, plus the same needless-return. Baseline main was
not clippy-clean with -D warnings before; after this pass one
needless_range_loop warning remains (live.rs:1089) that clippy's
suggested rewrite would make less readable — left for a dedicated
refactor session.

Build + workspace tests remain green (245 passing, 0 failing, 1
ignored).

crates/hotkey/src/linux.rs

@@ -343,14 +343,14 @@ async fn device_listener(
 fn is_event_device(path: &Path) -> bool {
     path.file_name()
         .and_then(|n| n.to_str())
-        .map_or(false, |n| n.starts_with("event"))
+        .is_some_and(|n| n.starts_with("event"))
 }
 
 /// Return true when the device's reported key set includes the combo's
 /// configured trigger key. A device that reports no keys at all (for
 /// example a mouse whose `EV_KEY` capability is buttons only) is rejected.
 fn device_supports_combo(supported: Option<&AttributeSetRef<Key>>, combo: &HotkeyCombo) -> bool {
-    supported.map_or(false, |keys| keys.contains(Key::new(combo.key_code)))
+    supported.is_some_and(|keys| keys.contains(Key::new(combo.key_code)))
 }
 
 #[cfg(test)]