Add UX optionality settings

[thomaseleff]

During early stages of implementation, user's may want to "try" out various UX options for various elements. Moving forward, each streamer web-app feature should ship with 2-3 UX options that a user can select between / enable within the Settings tab.

For example, here is a recent anecdote,

Can we keep the checkbox for muting a speaker, but label is as “enabled” and flip its meaning so that checked means that the speaker will play, and unchecked means it will be silent? I keep checking the box to enable a speaker and then remembering that it’s for mute (yes, I know, the word mute is right next to it 🤓). I really like the feature you added last time where the volume slider becomes grayed out when a speaker is disabled / muted.

Why
Allowing for / always shipping with optionality means we can remove the ambiguity of "what we like" by not having to imagine different UX - users can immediately experiment with different UX and report their favorite.

To do

• Write a new ADR describing the UX optionality approach, update / add coding agent instructions within the ui sub-package noting the optionality requirement
• Add optionality for existing UX options these should be organized as feature-flags, e.g., FF_DISABLED_VS_MUTE,
  • Remove the existing "host" settings in favor of Features settings
    • Each feature should be organized by the experience, like "Player Selection" and leverage a button group for options, allowing only a single button selection at a time. A button selection would then enable a particular feature-flag and force a refresh.
• Add the "Player Selection" feature
  • Add FF_DISABLED_VS_MUTE, when default (not enabled), the existing MUTE experience is used, otherwise, a new DISABLED experience is used.
  • For the DISABLED experience, instead of the Mute checkbox, each player should have a toggle to the left of the name, by default enabled. On disable, the card should be minimized to a single line (no more player settings info, no more volume slider). Disabling a player also mutes the player.
• Add the "Volume" feature
  • Add FF_VOLUME_PERC_OR_DB, when default (not enabled), the existing percentage based volume experience is used, otherwise, a new DB experience is used.
  • For the DB experience, instead of the slider representing a percentage, the slider should represent DB.
  • new For both modes, the UI should also display the current value in small gray font to the right of the slider
  • new For both modes, the UI should also display the material volume_up icon to the left of the slider
• Route the feature-flag settings through the DAL to ensure they are persisted on restarts