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).

src-tauri/src/lib.rs

@@ -234,7 +234,7 @@ pub fn run() {
             // Runtime-warning banner: push CPU-feature + Vulkan-loader
             // fallbacks to the frontend so Settings can render a one-line
             // hint. No-ops on a fully-supported box.
-            crate::commands::models::emit_runtime_warnings(&app.handle());
+            crate::commands::models::emit_runtime_warnings(app.handle());
 
             if let Err(e) = tray::setup(app) {
                 eprintln!("Failed to setup tray: {e}");