feat: add billing type tracking and cost enhancements

Add AdapterBillingType (api/subscription/unknown) to adapter execution results
so the system can distinguish API-billed vs subscription-billed runs. Enhance
cost service to aggregate subscription vs API run counts and token breakdowns.
Add limit param to heartbeat runs list API and client.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/adapter-utils/src/index.ts

@@ -2,6 +2,7 @@ export type {
   AdapterAgent,
   AdapterRuntime,
   UsageSummary,
+  AdapterBillingType,
   AdapterExecutionResult,
   AdapterInvocationMeta,
   AdapterExecutionContext,

packages/adapter-utils/src/types.ts

@@ -30,6 +30,8 @@ export interface UsageSummary {
   cachedInputTokens?: number;
 }
 
+export type AdapterBillingType = "api" | "subscription" | "unknown";
+
 export interface AdapterExecutionResult {
   exitCode: number | null;
   signal: string | null;
@@ -46,6 +48,7 @@ export interface AdapterExecutionResult {
   sessionDisplayId?: string | null;
   provider?: string | null;
   model?: string | null;
+  billingType?: AdapterBillingType | null;
   costUsd?: number | null;
   resultJson?: Record<string, unknown> | null;
   summary?: string | null;