fix(core): requeue HTTP ingest failures

[Tyagiquamar]

Summary

• detect HTTP failure responses from native fetch
• re-queue failed ingest batches for the existing retry path
• add regression coverage for a resolved 503 response

Root Cause

Native fetch resolves normally for HTTP 4xx and 5xx responses. The transport only handled rejected promises, so a non-2xx ingest response removed the batch from the queue permanently.

Verification

• pnpm --filter @smooai/observability exec vitest run src/__tests__/transport.test.ts passed: 7 tests
• pnpm --filter @smooai/observability typecheck passed
• pnpm exec oxfmt --check packages/core/src/transport.ts packages/core/src/__tests__/transport.test.ts passed
• git diff --check passed

Post-Deploy Monitoring & Validation

The existing ingest failure retry path remains the validation signal. No new production metric or configuration is introduced.

[changeset-bot]

🦋 Changeset detected

Latest commit: e8676af

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@smooai/observability	Patch

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[Tyagiquamar]

Hi, friendly ping for review on this PR when you have a moment. Happy to address any feedback. Thanks!