[SEA-NodeJS] (3/8) Kernel ErrorCode → JS error-class mapping (M0 minimum)

[msrathore-db]

Stack

Linear stack of 8 PRs landing the M0 + M1 Phase 1 SEA NodeJS work. Merge in order from base ↑ to tip. The tip branch (msrathore/sea-auth-u2m, PR #383) is the single snapshot containing everything in flight — point your test or benchmark harness at it for an end-to-end check.

Pos	PR	Branch	Scope
1/8	#378	sea-abstraction	IBackend / ISessionBackend / IOperationBackend interfaces
2/8	#380	sea-napi-binding	TS loader + build script for the kernel-provided .node artifact
3/8	#377	sea-errors-logging	Kernel ErrorCode → JS error-class mapping (M0 minimum)
4/8	#379	sea-auth	PAT auth via useSEA: true
5/8	#382	sea-execution	executeStatement + openSession (sessionConfig, initialCatalog/Schema)
6/8	#381	sea-results	CloudFetch + Inline Arrow result fetching
7/8	#384	sea-operation	cancel / close / finished lifecycle + INTERVAL parity + napi-relocation acceptance (absorbed sea-integration content)
8/8	#383	sea-auth-u2m ← TIP	M1 Phase 1 OAuth M2M + U2M (5 review rounds, ZERO HIGH at close)

Companion kernel stack (databricks/databricks-sql-kernel): 8 PRs — root #26 (async-public-api) → #27 → #25 → #29 → #28 → #30 → #24 → #23 (tip).

Policy: new PRs always stack on the current tip. No sibling/parallel topology. No force-pushes on existing PRs unless absolutely necessary; if a PR's content is wrong, add a fix-up commit on top of the stack tip rather than rewriting history.

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This PR is position 3/8.

Summary

SeaErrorMapping.ts decodes the kernel's __databricks_error__:<json> napi error envelope into typed JS errors (AuthenticationError, NetworkError, OperationStateError, etc.). M0-minimum mapping covers 13 kernel ErrorCode variants.

The decoder gets significantly hardened later in #383 (M1 OAuth) — namespace under error.kernelMetadata.*, sentinel-strip on corrupted envelopes, type-guards — but the M0 baseline is here.

Draft until you give the go for review.

Co-authored-by: Isaac

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[github-actions]

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