/**
 * Maps a Pi activity label to a distinguishing glyph for the heartbeat line.
 *
 * The heartbeat carries the activity as a LABEL STRING (e.g. "editing
 * run-step.ts"), not a structured kind — that is all that survives the
 * pi-agent → run-step → heartbeat pipeline. Rather than replumb a structured
 * activity-kind through the whole event chain (event shape, pi-agent, the
 * Telegram sink) for a cosmetic glyph, we key off the label's LEADING VERB,
 * which `pi-activity` produces as a stable contract ("editing"/"reading"/
 * "writing"/"running"/"searching"/"finding"/"listing"). Presentation stays in
 * this render-layer helper; the domain label stays text-only.
 *
 * Pure and total: an unrecognised or empty label degrades to the thinking glyph
 * rather than throwing. In the real pipeline `pi-activity` always emits a known
 * leading verb (unknown tools become `running <tool>`), so the fallback only
 * fires for a Pi thought line or rotating flavor text — 💭 fits both.
 */
export declare function activityGlyph(label: string): string;