macOS pre-push blocked: 11 clippy -D warnings errors in macOS-gated shell code

[oxoxDev]

Summary

Since #4872 (chore(rust): enforce warning-free clippy, merged 2026-07-16) the .husky/pre-push hook runs pnpm rust:clippy, which lints both crates with -D warnings. The Tauri shell crate (app/src-tauri) has 11 pre-existing clippy errors, all inside #[cfg(target_os = "macos")] code. This hard-blocks git push on every macOS dev machine.

Why CI is green

The Rust Quality job runs on ubuntu-22.04. macOS-gated regions are stripped before clippy runs, so these 11 lints are invisible to CI. Main is green; macOS devs are blocked. (The CI blind-spot itself is tracked separately.)

The 11 errors

File	Lint
app/src-tauri/src/lib.rs:1198,1261,1280	needless_return ×3
app/src-tauri/src/claude_code.rs:46	needless_return
app/src-tauri/src/native_notifications/mod.rs:40,54	needless_return ×2
app/src-tauri/src/imessage_scanner/mod.rs:375	contains() over iter().any()
app/src-tauri/src/mascot_native_window.rs:55	dead_code — webview field (RAII keep-alive, must stay)
app/src-tauri/src/mascot_native_window.rs:392	explicit_auto_deref
app/src-tauri/src/notch_window.rs:64	dead_code — is_open fn (zero callers)
app/src-tauri/src/notch_window.rs:265	explicit_auto_deref

Scope

Mechanical lint fixes only. Two judgment calls: MascotPanel.webview is an RAII keep-alive (documented in-struct) — #[allow(dead_code)], not deletion; notch_window::is_open has zero callers — delete. Vendored tauri-runtime-cef warnings are out of scope (path dep, not denied).

Acceptance

pnpm rust:clippy from repo root exits 0 on macOS.