Note Mapper
- Added a Show matching fret positions toggle for switching between note discovery and focused fretboard arrangement.
- Added exact fret-position selection so chord shapes can stay locked to the string and fret positions chosen by the user.
- Added the ability to remove individual piano-matched frets while refining a selected chord shape.
- Made repeated selection of an active pitch clear it consistently from both the piano and fretboard.
- Fixed local-storage hydration so saved Note Mapper preferences do not cause server and client render mismatches.