Function handle_event 

pub fn handle_event(
    ev: &Event,
    app: &mut AppState,
    query_tx: &UnboundedSender<QueryInput>,
    details_tx: &UnboundedSender<PackageItem>,
    preview_tx: &UnboundedSender<PackageItem>,
    add_tx: &UnboundedSender<PackageItem>,
    pkgb_tx: &UnboundedSender<PackageItem>,
    comments_tx: &UnboundedSender<String>,
) -> bool

What: Dispatch a single terminal event (keyboard/mouse) and mutate the AppState.

Inputs:

• ev: Terminal event (key or mouse)
• app: Mutable application state
• query_tx: Channel to send search queries
• details_tx: Channel to request package details
• preview_tx: Channel to request preview details for Recent
• add_tx: Channel to enqueue items into the install list
• pkgb_tx: Channel to request PKGBUILD content for the current selection

Output:

• true to signal the application should exit; otherwise false.

Details:

• Handles active modal interactions first (Alert/SystemUpdate/ConfirmInstall/ConfirmRemove/Help/News).
• Supports global shortcuts (help overlay, theme reload, exit, PKGBUILD viewer toggle, change sort).
• Delegates pane-specific handling to search, recent, and install submodules.