effect: classify AiError.InvalidResponseError as malformed-response #376

effect 4.0.6 adds a non-retryable AiError.InvalidResponseError reason for provider response-schema and SSE decoding failures. Its release notes ask exhaustive AiErrorReason matches to handle the new tag.

classifyReason in packages/effect/src/errors.ts is not exhaustive. An AiError with this reason (only another effect/ai provider can produce one, because this bridge never does) falls through to the HTTP-status check:

• With a 5xx HTTP context, classifyError returns "provider-unavailable" and isTransient returns true, but effect marks the reason non-retryable.
• With no status, it returns "unknown".

Proposed fix: add case "InvalidResponseError": to the "malformed-response" group next to InvalidOutputError/StructuredOutputError, with a unit test in packages/effect/test/errors.test.ts.

Found while bumping effect to 4.0.6 in the daily dependency batch (branch deps-batch-oct23). Recheck trigger: before the effect 0.1.0 release (#325) merges.

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