[GH-3260] Add ST_EqualsIdentical across Sedona SQL engines

[jiayuasu]

Did you read the Contributor Guide?

• Yes, I have read the Contributor Rules and Contributor Development Guide.

Is this PR related to a ticket?

• Yes, and the PR name follows the format [GH-XXX] my subject.

Part of #3260.

Depends on #3265.

What changes were proposed in this PR?

• Add a common ST_EqualsIdentical implementation that compares exact geometry type, nested structure, component and coordinate order, dimensionality, and every XY/Z/M ordinate.
• Treat corresponding NaN ordinates as equal, treat positive and negative zero as equal, and ignore SRID and other geometry metadata.
• Register and expose the predicate through:
  • Spark SQL, DataFrame APIs, Spark Connect, and the Python Spark SQL API
  • Flink SQL
  • Snowflake WKB and native GEOMETRY UDF paths
• Add SQL documentation for Spark, Flink, and Snowflake, including Snowflake's stored-geometry precision and dimensionality boundary.

This is the second PR in the #3260 stack and is based on the serializer branch from #3265.

How was this patch tested?

• Full common test suite: 1,297 tests passed.
• Spark predicate suite: 37 tests passed.
• Spark DataFrame API suite: 261 tests passed.
• Focused Flink predicate test passed.
• Snowflake DDL tests passed, and both modified Snowflake tester suites compiled successfully.
• Regression coverage includes XY/Z/M/ZM distinctions, NaN and infinity handling, typed empties, component and ring ordering, SRID independence, null propagation, and API argument validation.
• The repository commit-hook suite, Spotless, documentation build, Markdown linting, and git diff --check passed.

Did this PR include necessary documentation updates?

• Yes, I am adding a new API. I am using the current SNAPSHOT version, v2.0.0.
• Yes, I added Spark, Flink, and Snowflake SQL documentation.