Get bookability + effective capacity over a date range

Returns one row per (date × service period) in the window. Each row carries true guest bookability from the shared date-gate (open, closed_reason, closed_reason_kind of CLOSURE_PERIOD|SCHEDULE_EXCEPTION|WAITLIST_ONLY|INACTIVE_DAY|NO_SERVICE, waitlist_only) — the same gate the guest engine uses, so operator-closed nights (ClosurePeriod OR CLOSED Schedule Exception) report open:false instead of falsely showing floor capacity. Waitlist rows (state:"waitlist") additionally carry waitlist_rule_id, waitlist_scope (restaurant | service_period) and the rule's closed_from/closed_to window, so the caller sees WHICH rule holds the date and can lift it (DELETE /api/v1/availability-rules/:id) or book past it (POST /bookings force_closed:true). Capacity fields (effective_cap, cap_source override>default>floor, confirmed covers, remaining headroom) are populated only on open/waitlist rows and null on closed rows. Range capped at 60 days. Scope: bookings:read.