- New shared PracticeFilter settings (keyTonic/keyMode/fretWindow), persisted
via AppSettings.practice, defaults off (behavior unchanged).
- music/targetPool.ts: single source for the effective target pool —
base playable range ∩ fret window ∩ key/mode pitch classes (9 modes incl.
pentatonic, same scale machinery as Phrase Mode).
- useGameLogic now builds validNotes via computeTargetPool.
- TargetNoteControls component (key on/off + tonic/mode, fret window on/off +
min/max) rendered in Controls for all game modes; key is independent of the
displayed key signature.
- Phrase Mode binds its key/fret-window setup to the same shared filter
(read/write mirror) and drops the duplicate controls in its setup panel.
- Tests: targetPool.test.ts (7 cases); suite 156/156 green, build ok.
