SqlCompiler: provide comment & hint info

comment & hint info may useful in SparkFE @tobegit3hub
Used to determine whether fallback to SparkSQL

Look at the SqlCompiler component in the OpenMLDB codebase to understand how SQL is parsed and compiled. The issue mentions providing comment and hint info for SparkFE, likely for fallback decisions to SparkSQL. Investigate where SQL statements are processed and how metadata like comments/hints can be attached. Check for existing integration with Spark or SparkSQL to see how this info would be used.

由索引模型根据 Issue 内容生成。