fix Windows tray launch and Claude detection

[Danielweng0902]

Summary

• Honor Windows shortcut menubar / tray launch args on cold start.
• Reopen the tray panel when state says tray panel is active but the window is hidden.
• Keep Claude desktop detection on OAuth when no manual Claude cookie is configured.
• Fall back from unsupported Claude CLI usage output to OAuth.
• Use the current Claude OAuth usage endpoint and parse snake_case usage fields.
• Hide Windows where.exe probes to avoid flashing a console window.

Tests

• cargo fmt --manifest-path Cargo.toml --all --check
• cargo test --manifest-path rust/Cargo.toml providers::claude::oauth::tests --lib
• cargo test --manifest-path rust/Cargo.toml providers::claude::tests --lib
• cargo test --manifest-path apps/desktop-tauri/src-tauri/Cargo.toml fetch_context_claude
• cargo test --manifest-path apps/desktop-tauri/src-tauri/Cargo.toml tray_toggle_hides_only_when_panel_window_is_visible
• cargo test --manifest-path apps/desktop-tauri/src-tauri/Cargo.toml launch_arg -- close_request
• cargo run -p codexbar -- usage -p claude --source cli --json

[Finesssee]

Hey, thanks for the PR