v2.34.0 — Live schedule preview: your next three dates

📅 Live schedule preview — your next three dates (#83)

While editing a task's schedule, the dialog now shows the next three concrete occurrences the current settings produce — weekday-prefixed ("Sat 01/09/2027"), updating live as you change fields, with the schedule time appended and an "assuming on-time completion" note on completion-anchored intervals. Finite series show where they end.

The dates come from the REAL scheduling engine via a new read-only schedule/preview WebSocket command — never a frontend reimplementation, so season windows, business-day rolls, ±offsets and series ends are always exact. Verified end to end, including under a faked clock (libfaketime at 2026-12-01) with exact expected occurrence lists.

🐛 Fixed: seasonal window now preserves calendar patterns

A calendar-pattern task (e.g. "2nd Saturday") with a seasonal window came due on the 1st of the next active month instead of its pattern date — a "2nd Saturday of Jan+Jul" setup fired on Jan 1st. The seasonal roll now recomputes the pattern inside the active month (Sat Jan 9th), searching onward when a month lacks the pattern (e.g. a 5th Tuesday). Interval schedules keep the documented roll to the month's 1st.

2,827 backend + 281 frontend tests.