fix(appointment): make resource bookings independent of the doctor's calendar

Booking a device is not booking its doctor: the operator runs it and the doctor
only supervises. But bookAtomically locked the doctor row and isSlotTaken checked
overlap against the doctor alone, ignoring which resource was chosen, so a clinic
whose devices share one supervisor could not run two of them at once. Every
tenant in the database is in that position — clinic 2's six resources all point
at doctor 6.

Resource bookings now skip the doctor lock and carry no active_slot_key; their
guarantee comes from resource_occupancy, which understands capacity and seats.
Both direct paths write occupancy rows the way the hold engine already did, so
ResourceBookingSlotService stops being the only thing holding two sources of
truth together, and cancelling releases the seat.

Occupancy is bucketed in five-minute slices, which is coarser than a booking
time: a booking ending 12:35:04 spilled four seconds into the 12:35 bucket and
collided with the next one starting at that same second, despite zero real
overlap. This surfaced on real rows 76 and 77 during backfill. Resource bookings
now snap both ends of their window down to the bucket grid — schedule-driven
slots are already aligned, so only manually entered times move.

The seat is claimed after persist because it needs the appointment id; losing
the race removes the appointment rather than leaving a booking with no device
behind it.

app:appointment:backfill-resource-occupancy gives existing resource-backed
appointments their missing occupancy and clears the doctor keys that no longer
mean anything. It reports conflicts between two old bookings instead of picking
a loser.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/Appointment/Repository/AppointmentRepository.php

@@ -39,6 +39,20 @@ class AppointmentRepository extends ServiceEntityRepository
                 $start  = $appointment->getSlotStart();
                 $end    = $appointment->getSlotEnd();
 
+                /**
+                 * رزروِ منبع از تقویم پزشک مستقل است: دستگاه را اپراتور کار می‌کند و
+                 * پزشک فقط ناظر است. قفل و بررسیِ per-doctor اینجا اعمال نمی‌شود،
+                 * وگرنه کلینیکی که چند دستگاه زیر نظر یک پزشک دارد نمی‌تواند دوتایشان
+                 * را هم‌زمان رزرو کند. یکتاییِ خودِ منبع را
+                 * `uniq_bucket_resource_seat` تضمین می‌کند که ظرفیت و صندلی می‌فهمد.
+                 */
+                if ($appointment->getResource() !== null) {
+                    $em->persist($appointment);
+                    $em->flush();
+
+                    return;
+                }
+
                 // قفلِ per-doctor (SELECT ... FOR UPDATE روی ردیف پزشک): رزروهای
                 // هم‌زمانِ یک پزشک را سریالایز می‌کند. در حالت نوبت‌دهی سرویسی که
                 // نوبت‌ها طول متغیر و شروعِ متفاوت دارند، unique-keyِ (doctor,slot_start)