feat: add configurable pi statusbar extension

usage.ts

@@ -0,0 +1,98 @@
+export type Provider = "openai-codex" | "zai" | "anthropic";
+
+export type UsageUnit = "percent" | "tokens" | "requests" | "usd" | "minutes" | "bytes" | "unknown";
+
+export type UsageStatus = "ok" | "warning" | "exhausted" | "unknown";
+
+export interface UsageWindow {
+  id: string;
+  label: string;
+  durationMs?: number;
+  resetsAt?: number;
+}
+
+export interface UsageAmount {
+  used?: number;
+  limit?: number;
+  remaining?: number;
+  usedFraction?: number;
+  remainingFraction?: number;
+  unit: UsageUnit;
+}
+
+export interface UsageScope {
+  provider: Provider;
+  accountId?: string;
+  projectId?: string;
+  orgId?: string;
+  modelId?: string;
+  tier?: string;
+  windowId?: string;
+  shared?: boolean;
+}
+
+export interface UsageLimit {
+  id: string;
+  label: string;
+  scope: UsageScope;
+  window?: UsageWindow;
+  amount: UsageAmount;
+  status?: UsageStatus;
+  notes?: string[];
+}
+
+export interface UsageReport {
+  provider: Provider;
+  fetchedAt: number;
+  limits: UsageLimit[];
+  metadata?: Record<string, unknown>;
+  raw?: unknown;
+}
+
+export interface UsageLogger {
+  debug(message: string, meta?: Record<string, unknown>): void;
+  warn(message: string, meta?: Record<string, unknown>): void;
+}
+
+export interface UsageCredential {
+  type: "api_key" | "oauth";
+  apiKey?: string;
+  accessToken?: string;
+  refreshToken?: string;
+  expiresAt?: number;
+  accountId?: string;
+  projectId?: string;
+  email?: string;
+  enterpriseUrl?: string;
+  metadata?: Record<string, unknown>;
+}
+
+export interface UsageFetchParams {
+  provider: Provider;
+  credential: UsageCredential;
+  baseUrl?: string;
+  signal?: AbortSignal;
+}
+
+export interface UsageFetchContext {
+  fetch: typeof fetch;
+  logger?: UsageLogger;
+}
+
+export interface UsageProvider {
+  id: Provider;
+  fetchUsage(params: UsageFetchParams, ctx: UsageFetchContext): Promise<UsageReport | null>;
+  supports?(params: UsageFetchParams): boolean;
+}
+
+export interface CredentialRankingStrategy {
+  findWindowLimits(report: UsageReport): {
+    primary?: UsageLimit;
+    secondary?: UsageLimit;
+  };
+  windowDefaults: {
+    primaryMs: number;
+    secondaryMs: number;
+  };
+  hasPriorityBoost?(primary: UsageLimit | undefined): boolean;
+}