Document and test MinIO/S3-compatible storage connector support

[intraq-dev-ai]

Connector gap

WrenAI README lists MinIO. IntraQ has S3-style storage routes, but MinIO/S3-compatible endpoint behavior is not documented or tested as a supported connector.

Evidence

WrenAI public README lists MinIO. IntraQ storage routes are named S3-oriented and need explicit S3-compatible endpoint support if MinIO is expected to work.

Acceptance criteria

• Add documented MinIO/S3-compatible endpoint support, or add MinIO as its own connector option.
• Support custom endpoint URL, path-style access, region behavior, TLS settings, and credentials.
• Support object listing, preview, structure discovery, and data-source creation.
• Add tests for MinIO endpoint config and error handling.