Act as a startup finance lead. Calculate runway for {{startup_name}} from these figures: cash in the bank, {{cash_balance}}; monthly revenue and growth rate, {{revenue_and_growth}}; and monthly costs by category, including planned hires, {{monthly_costs}}. Show every formula: gross burn (total monthly spending), net burn (gross burn minus revenue), and runway in months (cash divided by net burn). Then project cash month by month for 18 months with the growth and cost changes I listed, and name the month cash falls below three months of net burn. Return: a burn and runway summary; the monthly projection table; three scenarios (as planned, revenue 30 percent lower, and costs cut 15 percent); the five levers that extend runway most, with the months each adds; and when to start fundraising if a round takes six months. List all assumptions. These are planning estimates, so suggest checking major decisions with a qualified accountant or advisor.