Per-agent colors in the collapsed Agent sidebar

[Gbone3176]

idea / problem

ui.sidebar.agents.rows_by_agent only affects the expanded Agent sidebar. When the sidebar is collapsed (ui.sidebar_collapsed_mode = "compact"), every agent entry renders as a single state logo colored by the global state-semantic theme colors. The per-agent identity is lost exactly in the view many of us keep on screen all the time: after collapsing the sidebar, all logos switch back to the same state colors, so "which agent is this" is only visible while the sidebar is expanded.

theme.custom.* is not a substitute — it restyles state colors globally, not per agent. And compact mode currently exposes no row/icon/color customization at all (config reference, v0.8.2 / v0.9.5).

requested change

Let the collapsed logo take its color (fg/bold/dim) from the state_icon style of the matching rows_by_agent override, falling back to the current behavior when no override exists. State glyphs stay exactly as they are, so the collapsed view still shows idle/working/blocked/done — just tinted with the agent's color.

Alternative shapes that would also work:

• a dedicated collapsed_rows / collapsed_rows_by_agent config with the same token model, or
• a single per-agent accent color that drives both the expanded and collapsed presentations.

I have a working prototype on top of v0.8.2 (one small renderer change in render_sidebar_collapsed: merge the state_icon token style from rows_for_agent(entry.agent); no override → unchanged behavior). Happy to open a PR if the direction sounds good.

why you want this

I run several agent flavors side by side (Codex, Kimi Code, Claude Code) and want to know at a glance which agent a row belongs to. Per-agent color families work beautifully in the expanded sidebar:

[ui.sidebar.agents.rows_by_agent]

codex = [
  [ { token = "state_icon", fg = "#d2a8ff" }, { token = "agent", fg = "#d2a8ff", bold = true }, { token = "$model", dim = true }, { token = "state_text" } ],
  [ { token = "$task" } ],
]
kimi = [
  [ { token = "state_icon", fg = "#79c0ff" }, { token = "agent", fg = "#79c0ff", bold = true }, { token = "$model", dim = true }, { token = "state_text" } ],
]
claude = [
  [ { token = "state_icon", fg = "#ffa657" }, { token = "agent", fg = "#ffa657", bold = true }, { token = "$model", dim = true }, { token = "state_text" } ],
]

I usually keep the sidebar collapsed for screen space, which means losing that signal most of the time. Tinting collapsed logos by agent would keep the collapsed view information-dense without adding any new UI surface.

Environment: herdr 0.8.2 (linux x86_64, stable), ui.sidebar_collapsed_mode = "compact", ui.status_indicators = "symbols".