draft: feat: databricks connector

[royendo]

Adds a Databricks connector that connects to Databricks SQL warehouses via the databricks-sql-go driver, supporting both OLAP queries and warehouse-based data export.

• Backend driver (runtime/drivers/databricks/) with OLAP store, information schema browsing (catalogs, schemas, tables), and warehouse interface (QueryAsFiles for Arrow/Parquet export)
• Connection via host, HTTP path, and personal access token; optional catalog and schema defaults
• DialectDatabricks added to the OLAP dialect enum
• Frontend schema with form fields for host, HTTP path, token, catalog, schema, plus table explorer (SQL + model name)
• Databricks Svelte icon components and connector icon mapping
• Documentation page with connection setup instructions

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!

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Developed in collaboration with Claude Code