Indicators

id	looks like	good for
`line`	heartbeat sparkline with a fill and a glowing “now” dot that breathes at `crit`	trends: load, latency, request rate
`gauge`	270° ring with warn/crit ticks, plus the value or `label` next to it	bounded values: %, quotas, battery
`dots`	LED dot matrix of the trend, each lit dot tinted by the value its row stands for, newest column glowing	the same as `line`, with more character

Set one per wing with "indicator": "<id>".

Writing your own

An indicator is a SwiftUI view that gets the wing’s state, config and health. Add a file to Sources/Polso/Indicators/:

import SwiftUI

/// Last N samples as bars.
enum BarsIndicator: Indicator {
    static let id = "bars"          // "indicator": "bars" in config
    static let label = "Bars"       // shown in Settings
    static func view(_ i: IndicatorInput) -> AnyView { AnyView(Bars(input: i)) }
}

struct Bars: View {
    var input: IndicatorInput

    var body: some View {
        let v = input.state.history.suffix(12)
        let top = max(v.max() ?? 1, input.config.crit ?? 0, 1e-9)
        HStack(alignment: .bottom, spacing: 2) {
            ForEach(Array(v.enumerated()), id: \.offset) { _, x in
                Capsule().fill(Health.ramp(x, input.config))
                    .frame(height: max(2, CGFloat(x / top) * 16))
            }
        }
        .padding(.horizontal, 8).padding(.vertical, 8)
    }
}

Then register it:

static let all: [IndicatorKind] = [LineIndicator.kind, GaugeIndicator.kind, DotsIndicator.kind, BarsIndicator.kind]

What you get in IndicatorInput:


`state.history`	`[Double]`, oldest first, capped at `history`
`state.value`	the latest sample
`state.label`	sender-provided text, if any
`config`	the wing’s `SlotConfig` (`warn`, `crit`, `max`, `unit`, `invert`…)
`health`	`.ok` `.warn` `.crit` `.unknown`, with `.color`

Helpers worth reusing: Sparkline, Dot, Health.ramp(v, config) for a continuous green→yellow→red, fmt(v, unit:) for numbers.

Keep idle cost at zero: no TimelineView or repeating animation unless the state calls for it (the built-ins only animate at crit). just snapshot renders every indicator to ./snapshots so you can check it without a notch.