feat(db): add usage tracking schema and types

Add database tables for proxy request logs and model pricing.
Extend Provider and error types to support usage statistics.

src/lib/query/usage.ts

@@ -0,0 +1,109 @@
+import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { usageApi } from '@/lib/api/usage';
+import type { LogFilters } from '@/types/usage';
+
+// Query keys
+export const usageKeys = {
+  all: ['usage'] as const,
+  summary: (startDate?: number, endDate?: number) =>
+    [...usageKeys.all, 'summary', startDate, endDate] as const,
+  trends: (days: number) => [...usageKeys.all, 'trends', days] as const,
+  providerStats: () => [...usageKeys.all, 'provider-stats'] as const,
+  modelStats: () => [...usageKeys.all, 'model-stats'] as const,
+  logs: (filters: LogFilters, limit: number, offset: number) =>
+    [...usageKeys.all, 'logs', filters, limit, offset] as const,
+  detail: (requestId: string) =>
+    [...usageKeys.all, 'detail', requestId] as const,
+  pricing: () => [...usageKeys.all, 'pricing'] as const,
+  limits: (providerId: string, appType: string) =>
+    [...usageKeys.all, 'limits', providerId, appType] as const,
+};
+
+// Hooks
+export function useUsageSummary(startDate?: number, endDate?: number) {
+  return useQuery({
+    queryKey: usageKeys.summary(startDate, endDate),
+    queryFn: () => usageApi.getUsageSummary(startDate, endDate),
+  });
+}
+
+export function useUsageTrends(days: number) {
+  return useQuery({
+    queryKey: usageKeys.trends(days),
+    queryFn: () => usageApi.getUsageTrends(days),
+  });
+}
+
+export function useProviderStats() {
+  return useQuery({
+    queryKey: usageKeys.providerStats(),
+    queryFn: usageApi.getProviderStats,
+  });
+}
+
+export function useModelStats() {
+  return useQuery({
+    queryKey: usageKeys.modelStats(),
+    queryFn: usageApi.getModelStats,
+  });
+}
+
+export function useRequestLogs(
+  filters: LogFilters,
+  limit: number = 50,
+  offset: number = 0
+) {
+  return useQuery({
+    queryKey: usageKeys.logs(filters, limit, offset),
+    queryFn: () => usageApi.getRequestLogs(filters, limit, offset),
+  });
+}
+
+export function useRequestDetail(requestId: string) {
+  return useQuery({
+    queryKey: usageKeys.detail(requestId),
+    queryFn: () => usageApi.getRequestDetail(requestId),
+    enabled: !!requestId,
+  });
+}
+
+export function useModelPricing() {
+  return useQuery({
+    queryKey: usageKeys.pricing(),
+    queryFn: usageApi.getModelPricing,
+  });
+}
+
+export function useProviderLimits(providerId: string, appType: string) {
+  return useQuery({
+    queryKey: usageKeys.limits(providerId, appType),
+    queryFn: () => usageApi.checkProviderLimits(providerId, appType),
+    enabled: !!providerId && !!appType,
+  });
+}
+
+export function useUpdateModelPricing() {
+  const queryClient = useQueryClient();
+
+  return useMutation({
+    mutationFn: (params: {
+      modelId: string;
+      displayName: string;
+      inputCost: string;
+      outputCost: string;
+      cacheReadCost: string;
+      cacheCreationCost: string;
+    }) =>
+      usageApi.updateModelPricing(
+        params.modelId,
+        params.displayName,
+        params.inputCost,
+        params.outputCost,
+        params.cacheReadCost,
+        params.cacheCreationCost
+      ),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: usageKeys.pricing() });
+    },
+  });
+}