feat(display): support selectable one-bit mode

[benletchford]

Summary

• accept one-bit framebuffer depth in runner and memory-bus configuration
• publish consistent one-bit QuickDraw/GDevice metadata and a two-entry palette
• accept --screen-depth 1 in the desktop CLI
• cover runner metadata and CLI parsing with focused regressions

Verification

• cargo test --lib one_bit_runner_publishes_consistent_screen_metadata
• cargo test --bin systemless cli_accepts_one_bit_screen_depth
• Beyond Dark Castle renders its title, menu, opening courtyard, HUD, movement, and jump animation in native monochrome mode

This is stacked on #568 because it extends the configurable 4/8-bit display API introduced there.

Closes #591.