feat(appkit): migrate analytics to the modular @databricks/sdk-*

[MarioCadenas]

What

Migrates the analytics stack (SQLWarehouseConnector + type-generator) off the legacy monolithic @databricks/sdk-experimental onto the new modular per-service @databricks/sdk-* SDK (v0.46.0, ESM-only), behind the existing packages/shared/src/workspace-client/ facade seam.

Analytics doesn't touch the SDK directly — it delegates to SQLWarehouseConnector, which uses two services: warehouses and statementExecution. Both move together in this increment; every other service (files/genie/jobs/serving/currentUser/apiClient) still routes through the legacy client behind the same facade (the seam's designed incremental state).

How

• New boundary module packages/shared/src/workspace-client/modular.ts — the sole importer of @databricks/sdk-* (oxlint no-restricted-imports boundary), mirroring legacy.ts. Builds per-service WarehousesClient / StatementExecutionClient; maps wrapper options → ClientOptions (host scheme-normalization, PAT empty-token privilege-escalation guard, profile); stamps process-global client-info (sanitized, best-effort).
• Connector + type-generator rewritten to the modular API: method renames (getStatement→getStatementResult, getStatementResultChunkN→getResultData), camelCase response model, CallOptions { signal } for cancellation.
• pnpm patch (patches/@databricks__sdk-statementexecution@0.46.0.patch) restores the undocumented Reyden attachment response field that the SDK's generated unmarshal transform would otherwise strip. Version-pinned — re-apply on any SDK bump; an upstream fix is preferred long-term.

Runtime bugs found + fixed (caught against live warehouses, not unit tests)

1. Host scheme — the modular SDK doesn't prepend https://; a bare DATABRICKS_HOST → Invalid URL. Fixed via normalizeHost.
2. Client-info — setProduct("@databricks/appkit") throws on @//; sanitized + wrapped best-effort.
3. ApiError.code — the modular ApiError carries the Databricks error code on .code, not .errorCode; the connector now reads either, so the arrow disposition/format capability-rejection fallback (INLINE↔EXTERNAL_LINKS) fires again.
4. BigInt serialization — the modular SDK types row/byte counts as bigint; Reyden's cached INLINE+ARROW_STREAM result then broke JSON.stringify. Counts are coerced back to number at the connector boundary.

Testing

• Full appkit + shared suites green (3877 passed / 1 skipped), including new regression tests for the .code read and bigint normalization.
• pnpm -r typecheck, lint, format clean.
• Verified live against standard + Reyden serverless warehouses: JSON + arrow (INLINE attachment and EXTERNAL_LINKS), OBO (.obo.sql), warehouse auto-start, metric views.

Notes

• Metric views run entirely on the migrated services (they compile to SQL); no separate migration needed.
• Regenerated the workspace-client API docs to match the new types (included).