feat: Add reusable modal and task detail view

Split the task detail modal into its own view and add a generic modal
frame, plus new models and service mapping for task details. Update app layout,
keymaps, and sidebar focus events to support the modal and keyboard flow, with small
UI tweaks like wrapping and scroll handling.

src/main.rs

@@ -2,6 +2,7 @@ use crate::app::App;
 
 mod app;
 mod components;
+mod dispatcher;
 mod keymap;
 mod models;
 mod task;