add global input bar across all views and unify priority color palette

Extract render_input_bar() from render_default_tab so the input field,
context bar, help line, and autocomplete appear on every tab. Remove
per-tab help bars. Handle Focus::Input globally before tab dispatch.

Shift priority colors to avoid collision with progress colors:
High → Magenta, Medium → Cyan. Use priority_icon() and priority_color()
consistently in kanban legend and suggestions tab.

Author: ComputelessComputer