feat: Add Spark SQL as a query engine

[ferenc-csaky]

Key Changes

• Add the sparksql query engine with Spark SQL statement generation backed by Iceberg deployment artifacts.
• Add Spark SQL Calcite conversion and dialect support, including backtick identifiers and Spark-native scalar, temporal, array, map, and struct type rendering.
• Refactor JDBC DDL generation to quote table, view, index, and column identifiers through the active SQL dialect.
• Make query-engine server configuration optional so engines without runtime server configuration, such as Spark SQL, are supported.
• Add a Spark SQL compile use case and snapshot covering primitive, temporal, binary, collection, row, and aggregate result types.

[codecov]

Codecov Report

❌ Patch coverage is 20.37037% with 86 lines in your changes missing coverage. Please review.
✅ Project coverage is 17.61%. Comparing base (8b8622f) to head (4e4dd6e).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...asqrl/calcite/dialect/ExtendedSparkSqlDialect.java	18.18%	27 Missing ⚠️
...engine/database/relational/ddl/CreateIndexDDL.java	0.00%	13 Missing ⚠️
...atasqrl/config/QueryEngineConfigConverterImpl.java	0.00%	7 Missing ⚠️
...qrl/engine/database/relational/SparkSqlEngine.java	0.00%	7 Missing ⚠️
.../database/relational/SparkSqlStatementFactory.java	0.00%	5 Missing ⚠️
.../database/relational/PostgresStatementFactory.java	0.00%	4 Missing ⚠️
...e/database/relational/ddl/DdlIdentifierQuoter.java	33.33%	3 Missing and 1 partial ⚠️
...se/relational/ddl/GenericCreateViewDdlFactory.java	0.00%	4 Missing ⚠️
...ine/database/relational/SparkSqlEngineFactory.java	0.00%	3 Missing ⚠️
...e/relational/ddl/GenericCreateTableDdlFactory.java	70.00%	3 Missing ⚠️
... and 8 more

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2241      +/-   ##
============================================
- Coverage     17.63%   17.61%   -0.02%     
- Complexity     1077     1082       +5     
============================================
  Files           610      617       +7     
  Lines         17762    17835      +73     
  Branches       2167     2168       +1     
============================================
+ Hits           3132     3142      +10     
- Misses        14312    14374      +62     
- Partials        318      319       +1     

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