Add attention inbox and AI usage observability

packages/api-contracts/src/stats.ts

@@ -74,5 +74,24 @@ export const FunnelResponseSchema = z.strictObject({
   images: z.number(),
 });
 
+const AiUsageFields = {
+  requests: z.number().int().nonnegative(),
+  successes: z.number().int().nonnegative(),
+  refusals: z.number().int().nonnegative(),
+  errors: z.number().int().nonnegative(),
+  promptTokens: z.number().int().nonnegative(),
+  completionTokens: z.number().int().nonnegative(),
+  totalTokens: z.number().int().nonnegative(),
+  costUsd: z.number().nonnegative(),
+  averageLatencyMs: z.number().nonnegative(),
+};
+
+export const AiUsageSummaryResponseSchema = z.strictObject({
+  days: z.number().int().positive(),
+  ...AiUsageFields,
+  models: z.array(z.strictObject({ model: z.string(), ...AiUsageFields })),
+});
+
 export type StatsResponse = z.infer<typeof StatsResponseSchema>;
 export type TimersResponse = z.infer<typeof TimersResponseSchema>;
+export type AiUsageSummaryResponse = z.infer<typeof AiUsageSummaryResponseSchema>;