Operator wants to trigger a scheduled prompt immediately
instead of waiting for the next interval. Adds a `↯ fire now`
button on every active schedule row, next to `✕ cancel all`.
Semantics (per design discussion with damocles):
- recurring schedules → out-of-band pulse, `next_fire_at_unix`
untouched; the regular cadence keeps firing on the original
schedule. Operator gets an extra fan-out, not a phase shift.
- one-shots → consumed after the manual fire. Operator's
intent reads as "the scheduled time was wrong, send NOW";
leaving the original time would be surprising.
Confirm dialog spells out the recurring-vs-one-shot
difference up front so the operator knows what they're about
to do. Button is disabled when every target is already
cancelled (nothing to fire).
Talks to `POST /api/schedules/{id}/fire-now` (damocles is
wiring the backend in parallel). Mauve styling distinguishes
it from cancel (red) and submit (amber); fits the existing
btn pattern.
docs/web-ui.md updated.