feat: expose YCQL port in devnet-info export

[redpanda-f]

This is needed as part of scenario tests for checking cassandra indexstore caches.

This does not break DevnetInfoV1, merely extends it, so no major version updates is required.

Part of #72

[Copilot]

Pull request overview

Extends the exported devnet-info.json schema to include YugabyteDB’s YCQL (Cassandra-compatible) port so scenario tests (e.g., Cassandra indexstore cache checks) can discover and connect to the correct CQL endpoint.

Changes:

• Add ycql_port to the YugabyteInfo schema.
• Populate ycql_port in the devnet-info exporter from the SetupContext (yugabyte_<id>_ycql_port).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/external_api/export.rs	Reads yugabyte_<provider_id>_ycql_port from the setup context and includes it in exported YugabyteInfo.
src/external_api/devnet_info.rs	Extends the YugabyteInfo struct with a new ycql_port field and documentation.

[Copilot]

YugabyteInfo is a public struct (re-exported via crate::external_api) and the crate is versioned as 1.x. Adding a new non-optional field is a semver-breaking API change for Rust consumers (struct literals / exhaustive patterns) and also makes deserializing older devnet-info.json (without ycql_port) fail. To keep this extension backward/forward compatible within schema v1, consider making ycql_port an Option<u16> with #[serde(default)] (and populate it as Some(...) in the exporter), or alternatively bump the exported schema version and introduce a v2 struct.

Suggested change

	pub ycql_port: u16,
	#[serde(default)]
	pub ycql_port: Option<u16>,