[audit] dead-code: unused Rust crates dispatch2 and block2 in Cargo.toml

[claude]

Problem

Two macOS-only Rust crate dependencies in src-tauri/Cargo.toml are never used in source code:

1. dispatch2 (line 54)

dispatch2 = "0.2" — zero imports. The only mention is a comment in src-tauri/src/pdf_export/renderer.rs:11 explaining why it was intentionally not used:

Uses app.run_on_main_thread() (tao event loop) instead of dispatch2::Queue::main().exec_async() (GCD).

2. block2 (line 58)

block2 = "0.6" — zero imports (block2:: never appears in source). Note that block2 is also listed as a feature of objc2-web-kit (line 55), which pulls it in transitively. The standalone dependency is unnecessary.

Impact

Dead dependencies increase compile time and binary size. dispatch2 pulls in additional GCD bindings that are never linked.

Suggested Fix

Remove both from [target.'cfg(target_os = "macos")'.dependencies]:

-dispatch2 = "0.2"
-block2 = "0.6"

Verify with cargo check --target aarch64-apple-darwin after removal.

Files

• src-tauri/Cargo.toml:54 (dispatch2)
• src-tauri/Cargo.toml:58 (block2)