feat(properties): expenses tab with electricity+water chart

- expense_kind enum (utilities + maintenance/repair/cleaning/insurance/tax/rent/other)
- property_expenses table with optional link to a property_accounts row
  (preserves history via ON DELETE SET NULL)
- services/expenses.ts: CRUD + 12-month monthly series aggregation +
  year-to-date summary by kind
- /properties/[id]/expenses tab: inline SVG line chart for electricity +
  water last 12 months (no chart library), summary card, add/edit/delete
  inline with account linking when kind matches

drizzle/0015_expenses_updated_at_trigger.sql

@@ -0,0 +1,3 @@
+-- Updated_at trigger for property_expenses.
+CREATE TRIGGER property_expenses_set_updated_at BEFORE UPDATE ON "property_expenses"
+	FOR EACH ROW EXECUTE FUNCTION set_updated_at();