fix(macos): ignore plain clicks without a selection gesture

[Ldsystem]

Summary

• ignore stationary single clicks before resolving Accessibility selection state
• preserve drag-based text selection
• preserve double- and triple-click word selection using Quartz click counts
• add regression coverage for gesture classification

Root cause

The macOS global input monitor forwarded every primary-button release to the selection resolver. Supported applications can retain stale Accessibility selection text after a normal click, which made the translation control appear without a new selection.

Verification

• cargo fmt --manifest-path src-tauri/Cargo.toml --check
• cargo clippy --manifest-path src-tauri/Cargo.toml --all-targets -- -D warnings
• cargo test --manifest-path src-tauri/Cargo.toml --lib — 153 passed, 7 ignored
• pnpm check — 81 passed, 5 skipped; typecheck and production build passed
• Chrome smoke: stationary click stayed silent; drag selection remained selectable
• Installed macOS app signature, checksum, single-process state, and SQLite quick check verified