[idea] Add separate theme tokens for sidebar workspace active/inactive styling

[RodriMora]

idea / problem

Currently, the sidebar workspace list appears to share theme tokens with other UI areas like tabs.

I wanted to style the active workspace in the left sidebar similarly to my tmux config:

• active workspace: blue background with bright/bold text
• inactive workspaces: dimmer text
• tabs: keep existing theme colors unchanged

Trying to do this through [theme.custom] affects tabs as well, because tokens like surface_dim, text, subtext0, and accent are reused across multiple UI elements.

Changing workspace-related appearance via theme overrides also changes tab colors and other UI elements.

Example:

[theme.custom]
surface_dim = "#005f87"
text = "#ffffff"
subtext0 = "#808080"
accent = "#0000ff"

requested change

Expose dedicated theme tokens for the sidebar workspace list, so users can customize workspace styling independently from tabs.

Possible tokens:

  [theme.custom]
  workspace_active_bg = "#005f87"
  workspace_active_fg = "#ffffff"
  workspace_active_indicator = "#0000ff"
  workspace_inactive_fg = "#808080"
  workspace_selected_bg = "..."
  workspace_dragged_bg = "..."

Or similar names.

why you want this

The workspace list is a distinct navigation surface from the tab bar. It would be useful to customize it independently, especially for users coming from tmux-style status/window styling.