GeezerVison

LGTM. This is a docs-only change, so the test gates don't apply.

What I ran

• pre-commit run --files helm-chart-reference.md passed.
• cargo test -p feldera-types local_file_uri passed.
• I checked the new row against TransportConfig::local_file_uris and resolve_connector_config in crates/connectors/src/controller.rs. The row matches what the code does:
  • Covered connectors: Delta input and output (uri), and Iceberg input (metadata_location, glue.warehouse).
  • What counts as local: a file: URL or a value with no scheme.
  • When it applies: the connector fails when it is created, and the check also runs on values that come from secrets.
• The Helm chart isn't in this repo, so I couldn't confirm the true default or that the chart maps the option to FELDERA_REFUSE_LOCAL_FILE_URIS.

missing (medium): docs/connectors/sources/iceberg.md:110 still lists file:// / no prefix as supported, and the Delta pages don't mention the restriction. Users on a locked-down deployment will hit a startup error that those pages don't explain. A one-line note on each page linking to this Helm option, and naming the env var for deployments that don't use Helm, would close that gap.