feat: X API Cost Crisis Alert Chrome extension MVP with cost calculator, 8 alternatives, and 12 passing tests

src/types.ts

@@ -0,0 +1,19 @@
+// ---- Types ----
+export interface ApiAlternative {
+  name: string;
+  website: string;
+  freeTier: string;
+  paidTier: string;
+  pricingUrl: string;
+  description: string;
+  features: string[];
+  bestFor: string;
+  xApiReplacement: string;
+}
+
+export interface CostEstimate {
+  monthlyReads: number;
+  monthlyWrites: number;
+  xCost: number;
+  alternatives: { name: string; cost: number | string }[];
+}