fix(provider): classify gateway quota exhaustion and 402 as non-retryable

[filipeforattini]

Summary

Ports the ideas from upstream opencode 4a27842 and 6a30741 to both runtimes.

• @reddb-io/redcode-llm: new isQuotaFailure / isContentPolicyFailure classifiers. Quota = HTTP 402, a quota code (insufficient_quota, usage_not_included, billing_error, usage_limit*, insufficient_credits, Zen FreeUsageLimitError / GoUsageLimitError / CreditLimitExceeded) wherever a provider or router puts it (including OpenRouter metadata.raw and Zen [code] labels), or quota/credits wording on a 429. Content policy = provider codes (content_filter, ResponsibleAIPolicyViolation, content_policy_violation, ...).
• RequestExecutor (v2): 402 and gateway caps become QuotaExceeded (not retried) instead of UnknownProvider / RateLimit.
• SessionRetry (core, both runtimes): quota and content-policy failures are never retried, even when the SDK marks a 429 retryable or the body says "try again". A 4xx other than 408/409/429 is only promoted to retryable by transport failures, so a gateway's substituted server_error on a 400 is no longer retried. Router-reported reasons (quota_exhausted with retry-at) keep router semantics.
• Legacy ProviderError.parseAPICallError / parseStreamError: quota failures are non-retryable and the message says the account's quota, credits or free-tier limit is exhausted.

Tests

• packages/llm/test/provider-error.test.ts, packages/llm/test/executor.test.ts
• packages/core/test/session-retry.test.ts
• packages/redcode/test/session/retry.test.ts (the FreeUsageLimitError/GoUsageLimitError case now expects no retry)

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