[Improvement]: Add mixed Flink 1.19 support to align with Iceberg engine support

[xxubai]

Search before asking

• I have searched in the issues and found no similar issues.

What would you like to be improved?

Amoro mixed-format Flink currently maintains version-specific modules for Flink 1.16, 1.17, and 1.18, but does not yet provide a Flink 1.19 variant.

According to Iceberg's multi-engine support matrix, Flink 1.19 is maintained. If we want to keep upgrading Iceberg with lower friction, Amoro should align its mixed-format Flink support with the engine versions that Iceberg continues to maintain.

How should we improve?

We should add mixed Flink 1.19 support to Amoro. This likely includes:

• adding v1.19/amoro-mixed-flink-1.19
• adding v1.19/amoro-mixed-flink-runtime-1.19
• updating parent module definitions and related CI/build jobs
• validating catalog, source/sink, and runtime compatibility under Flink 1.19
• updating documentation for the supported Flink version matrix

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Subtasks

• Add mixed Flink 1.19 modules
• Verify compile/tests for Flink 1.19
• Update CI/build matrix to include mixed Flink 1.19
• Update related documentation

Code of Conduct

• I agree to follow this project's Code of Conduct