feat: add harmony and audiowave timeline kinds to CLI add command

[FelipeDefensor]

Summary

• Adds harmony / har and audiowave / aud as valid kind arguments to timelines add.
• Harmony timelines omit the --height kwarg (their height is computed from level count and level height internally).
• Audiowave timelines similarly omit --height.
• Tests added for both new kinds and their abbreviations.

Test plan

• tilia timelines add harmony --name "Chords" creates a harmony timeline.
• tilia timelines add har works as shorthand.
• tilia timelines add audiowave --name "Wave" creates an audiowave timeline.
• tilia timelines add aud works as shorthand.

Closes #476