refactor(quota): move provider quota logic into adapter layer, add unit tests

- Extract all Anthropic credential/API logic into claude-local/src/server/quota.ts
- Extract all OpenAI/WHAM credential/API logic into codex-local/src/server/quota.ts
- Add optional getQuotaWindows() to ServerAdapterModule in adapter-utils
- Rewrite quota-windows.ts as a 29-line thin aggregator with zero provider knowledge
- Wire getQuotaWindows into adapter registry for claude-local and codex-local
- Add 47 unit tests covering toPercent, secondsToWindowLabel, WHAM normalization,
  readClaudeToken, readCodexToken, fetchClaudeQuota, fetchCodexQuota, fetchWithTimeout
- Add 8 unit tests covering parseDateRange validation and byProvider pro-rata math

Adding a third provider now requires only touching that provider's adapter.

packages/adapters/claude-local/src/server/index.ts

@@ -6,6 +6,14 @@ export {
   isClaudeMaxTurnsResult,
   isClaudeUnknownSessionError,
 } from "./parse.js";
+export {
+  getQuotaWindows,
+  readClaudeToken,
+  fetchClaudeQuota,
+  toPercent,
+  fetchWithTimeout,
+  claudeConfigDir,
+} from "./quota.js";
 import type { AdapterSessionCodec } from "@paperclipai/adapter-utils";
 
 function readNonEmptyString(value: unknown): string | null {

packages/adapters/claude-local/src/server/quota.ts

@@ -0,0 +1,117 @@
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+import type { ProviderQuotaResult, QuotaWindow } from "@paperclipai/adapter-utils";
+
+export function claudeConfigDir(): string {
+  const fromEnv = process.env.CLAUDE_CONFIG_DIR;
+  if (typeof fromEnv === "string" && fromEnv.trim().length > 0) return fromEnv.trim();
+  return path.join(os.homedir(), ".claude");
+}
+
+export async function readClaudeToken(): Promise<string | null> {
+  const credPath = path.join(claudeConfigDir(), "credentials.json");
+  let raw: string;
+  try {
+    raw = await fs.readFile(credPath, "utf8");
+  } catch {
+    return null;
+  }
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(raw);
+  } catch {
+    return null;
+  }
+  if (typeof parsed !== "object" || parsed === null) return null;
+  const obj = parsed as Record<string, unknown>;
+  const oauth = obj["claudeAiOauth"];
+  if (typeof oauth !== "object" || oauth === null) return null;
+  const token = (oauth as Record<string, unknown>)["accessToken"];
+  return typeof token === "string" && token.length > 0 ? token : null;
+}
+
+interface AnthropicUsageWindow {
+  utilization?: number | null;
+  resets_at?: string | null;
+}
+
+interface AnthropicUsageResponse {
+  five_hour?: AnthropicUsageWindow | null;
+  seven_day?: AnthropicUsageWindow | null;
+  seven_day_sonnet?: AnthropicUsageWindow | null;
+  seven_day_opus?: AnthropicUsageWindow | null;
+}
+
+/** Convert a 0-1 utilization fraction to a 0-100 integer percent. Returns null for null/undefined input. */
+export function toPercent(utilization: number | null | undefined): number | null {
+  if (utilization == null) return null;
+  // utilization is 0-1 fraction; clamp to 100 in case of floating-point overshoot
+  return Math.min(100, Math.round(utilization * 100));
+}
+
+/** fetch with an abort-based timeout so a hanging provider api doesn't block the response indefinitely */
+export async function fetchWithTimeout(url: string, init: RequestInit, ms = 8000): Promise<Response> {
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), ms);
+  try {
+    return await fetch(url, { ...init, signal: controller.signal });
+  } finally {
+    clearTimeout(timer);
+  }
+}
+
+export async function fetchClaudeQuota(token: string): Promise<QuotaWindow[]> {
+  const resp = await fetchWithTimeout("https://api.anthropic.com/api/oauth/usage", {
+    headers: {
+      "Authorization": `Bearer ${token}`,
+      "anthropic-beta": "oauth-2025-04-20",
+    },
+  });
+  if (!resp.ok) throw new Error(`anthropic usage api returned ${resp.status}`);
+  const body = (await resp.json()) as AnthropicUsageResponse;
+  const windows: QuotaWindow[] = [];
+
+  if (body.five_hour != null) {
+    windows.push({
+      label: "5h",
+      usedPercent: toPercent(body.five_hour.utilization),
+      resetsAt: body.five_hour.resets_at ?? null,
+      valueLabel: null,
+    });
+  }
+  if (body.seven_day != null) {
+    windows.push({
+      label: "7d",
+      usedPercent: toPercent(body.seven_day.utilization),
+      resetsAt: body.seven_day.resets_at ?? null,
+      valueLabel: null,
+    });
+  }
+  if (body.seven_day_sonnet != null) {
+    windows.push({
+      label: "Sonnet 7d",
+      usedPercent: toPercent(body.seven_day_sonnet.utilization),
+      resetsAt: body.seven_day_sonnet.resets_at ?? null,
+      valueLabel: null,
+    });
+  }
+  if (body.seven_day_opus != null) {
+    windows.push({
+      label: "Opus 7d",
+      usedPercent: toPercent(body.seven_day_opus.utilization),
+      resetsAt: body.seven_day_opus.resets_at ?? null,
+      valueLabel: null,
+    });
+  }
+  return windows;
+}
+
+export async function getQuotaWindows(): Promise<ProviderQuotaResult> {
+  const token = await readClaudeToken();
+  if (!token) {
+    return { provider: "anthropic", ok: false, error: "no local claude auth token", windows: [] };
+  }
+  const windows = await fetchClaudeQuota(token);
+  return { provider: "anthropic", ok: true, windows };
+}