feat: add occupancy percentage widget to dashboard

[errbchile]

feat: add occupancy percentage widget to dashboard

What

Adds a 5th widget to the dashboard showing the current occupancy rate: the percentage of rooms that have an active confirmed booking.

How

• Formula: confirmed_bookings / total_rooms * 100, rounded to 1 decimal place
• State filter: only Booking.NEW bookings are counted — cancelled ones (Booking.DELETED) are excluded
• Division-by-zero guard: returns 0.0 when no rooms exist

Files changed

File	Change
pms/views.py	Occupancy calculation in DashboardView.get(); datetime import moved to top-level
pms/templates/dashboard.html	5th widget card (purple) rendering {{ dashboard.occupancy }}%
pms/tests.py	DashboardOccupancyTest — 5 tests

Tests

Test	Covers
test_occupancy_is_zero_when_no_rooms_exist	Division-by-zero guard
test_occupancy_is_zero_when_no_confirmed_bookings	Rooms exist, no active bookings
test_occupancy_partial_percentage	1 of 2 rooms booked → 50.0%
test_occupancy_is_100_when_all_rooms_booked	All rooms booked → 100.0%
test_cancelled_bookings_not_counted	DEL bookings excluded