fix: normalizeRoom converts NUMERIC baseRate string to number in api.ts

PostgreSQL NUMERIC columns are returned as strings by node-postgres.
Added normalizeRoom() that coerces baseRate/hourlyRate/floor to JS numbers
before they reach components, eliminating string concatenation bugs like
"300005000.005000.00" in price calculations.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/bookings/BookingModal.tsx

@@ -337,13 +337,14 @@ export function BookingModal({ open, draft, rooms, bookings = [], onClose, onSav
     if (!room || !form.checkIn || nightCount <= 0) return 0
     const catId = room.categoryId
     const catOverrides = catId ? priceOverrides?.[catId] : undefined
-    const fallback = room.baseRate ?? 0
+    // room.baseRate is NUMERIC in DB — pg returns it as a string; always coerce
+    const fallback = Number(room.baseRate) || 0
     if (!catOverrides) return fallback * nightCount
     let sum = 0
     for (let i = 0; i < nightCount; i++) {
       const d = format(addDays(parseISO(form.checkIn), i), 'yyyy-MM-dd')
-      const p = catOverrides[d]
-      sum += (typeof p === 'number' && isFinite(p)) ? p : fallback
+      const p = Number(catOverrides[d])
+      sum += (isFinite(p) && p > 0) ? p : fallback
     }
     return sum
   })()