feat: Add SeaTable as native data source plugin

[christophdb]

Summary

Add SeaTable as a native data source plugin for Appsmith. SeaTable is an open-source database platform (spreadsheet-database hybrid) with a REST API, similar to Airtable.

Why SeaTable?

• Open source and self-hostable — fits well with Appsmith's philosophy
• REST API with token-based authentication
• SQL query support
• Growing user base, especially in Europe
• Currently no Appsmith plugin exists for SeaTable, Baserow, or NocoDB — SeaTable would be the first open-source Airtable alternative with native Appsmith support

Proposed Features

Command	Method	Endpoint
List Rows	GET	/api/v2/dtables/{uuid}/rows/
Get Row	GET	/api/v2/dtables/{uuid}/rows/{row_id}/
Create Row	POST	/api/v2/dtables/{uuid}/rows/
Update Row	PUT	/api/v2/dtables/{uuid}/rows/
Delete Row	DELETE	/api/v2/dtables/{uuid}/rows/
List Tables (Metadata)	GET	/api/v2/dtables/{uuid}/metadata/
SQL Query	POST	/api/v2/dtables/{uuid}/sql/

Authentication

SeaTable uses a two-step auth flow:

1. Exchange an API Token for a Base Access Token via GET /api/v2.1/dtable/app-access-token/
2. Use the Access Token for all subsequent API calls

Implementation

A complete implementation is ready at seatable/appsmith-connector, including:

• Native Java plugin (PluginExecutor<Void>, stateless HTTP via WebClient)
• UQI editor forms (like Firestore plugin)
• Schema discovery via getStructure()
• Unit tests with MockWebServer
• Database migration (ChangeSet)

All API endpoints have been verified against the SeaTable OpenAPI specification and tested against a live SeaTable instance.

References

• SeaTable API Reference
• SeaTable Developer Documentation
• Ready-to-merge connector code

[linear]

APP-15022