feat(core): add QuotaManager with exponential backoff and persistence

[iceteaSA]

Unified quota cache and API gateway for main + fallback quota state. All consumers share one QuotaManager instance for consistent caching.

Features:

• Inflight deduplication prevents concurrent API calls
• Exponential backoff (60s–15min) for 429/5xx errors with escalating retry counts
• Persists main quota and backoff state to disk via callbacks
• Cross-process file lock guard for quota API dedup
• Seeds from persisted storage on construction (avoids cold-start API call)
• Integrates with FallbackAccountManager for shared staleness checks
• Captures storage path at init to prevent test config corruption
• Request-count-based refresh trigger (refreshEveryNRequests)

Files:

• packages/core/src/quota-manager.ts — new (391 lines)
• packages/core/src/accounts.ts — adds backoff helpers, FallbackAccountManager integration
• packages/opencode/src/index.ts — QuotaManager construction, persistence callbacks, routing
• packages/opencode/src/tests/quota-manager.test.ts — new (294 lines)

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Summary by cubic

Adds a unified QuotaManager for main and fallback quotas with shared in-memory cache, a serial API gate, exponential backoff, and on-disk persistence. Integrates it into packages/opencode for routing and the quotas view, with fail-closed behavior when the Usage API is backed off and no cached quota is available.

• New Features

  • Single QuotaManager with inflight dedup, a serialized API gate, and a cross‑process file lock (main quota).
  • Exponential backoff for 429/5xx (60s up to 15m) with persisted state and callbacks (onMainQuotaFetched, onApiError); seeds backoff and main quota from disk on startup.
  • Request-count refresh trigger via quota.refreshEveryNRequests; staleness checks shared across processes.
  • Integrates with FallbackAccountManager: seeds from persisted fallback quotas, shared staleness, and gated refreshAllFallbacks.
  • packages/opencode: uses QuotaManager for routing and quotas view, persists main quota/backoff to disk, and adds fail‑closed behavior with 429 + retry-after when backed off and uncached; captures storage path at init.

• Migration

  • @cortexkit/anthropic-auth-core now exports QuotaManager.
  • If using FallbackAccountManager, pass a shared QuotaManager to unify cache and staleness.
  • To persist main quota/backoff, wire QuotaManager callbacks to save quota.mainQuota, quota.mainQuotaCheckedAt, and quota.mainLastQuotaApiError.

^{Written for commit 5938687. Summary will update on new commits. Review in cubic}

[cubic-dev-ai]

2 issues found across 6 files

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