Configurator: knob/encoder editor (screen binding + navigation ring + order badges)

[billmallard]

Configurator: knob/encoder editor (screen binding + navigation ring + order badges)

The editor UI for the physical rotary knob: bind the encoder to a screen, choose
which instruments it can reach and in what order, and (Phase B) how it edits them.

Spec: docs/knob_encoder_configurator.md (configurator side of Phases A/B).
Depends on the pyEfis encoder schema/capability export.

Scope (Phase A)

• Screen-level "Knob / encoder" panel: pick encoder / encoder_button keys
  (dropdown from the FIX catalogue, default ENC3/BTN3) + encoder_timeout. Emitted
  into the screens.<name> block.
• Per-instrument "Reachable by knob" toggle + a drag-to-order ring list; the
  big encoder_order integers are auto-generated (never hand-typed), raw
  value available as an advanced field.
• Canvas order-badge overlay: numbered badges on reachable instruments in ring
  order. This is the knob's stand-in for a twin (no on-screen widget to render).

Scope (Phase B)

• Per editable type, expose the simple edit options from the capability catalogue
  (encoder_set_key, encoder_multiplier, encoder_set_real_time,
  encoder_revert, confirm). Defer the digit-mask/radio-tuning family.

Acceptance

• Toggling "reachable" + reordering three instruments writes correct
  encoder_order values and renders badges 1/2/3 in order.
• The screen emits encoder/encoder_button/encoder_timeout.