feat: add initial application structure with configuration, UI components, and state management

composables/useRunway.ts

@@ -0,0 +1,27 @@
+/**
+ * Computes months of runway from cash, reserves, and burn rate
+ * Formula: (cash + savings) ÷ average monthly burn in scenario
+ */
+export const useRunway = () => {
+  const calculateRunway = (cash: number, savings: number, monthlyBurn: number): number => {
+    if (monthlyBurn <= 0) return Infinity
+    return (cash + savings) / monthlyBurn
+  }
+  
+  const getRunwayStatus = (months: number): 'green' | 'yellow' | 'red' => {
+    if (months >= 3) return 'green'
+    if (months >= 2) return 'yellow'
+    return 'red'
+  }
+  
+  const formatRunway = (months: number): string => {
+    if (months === Infinity) return '∞ months'
+    return `${months.toFixed(1)} months`
+  }
+  
+  return {
+    calculateRunway,
+    getRunwayStatus,
+    formatRunway
+  }
+}