Fix additional transpiler issues found during audit

[EDsCODE]

Summary

Comprehensive audit of the transpiler revealed additional issues similar to #126:

• Fix InformationSchemaTransform missing ColumnRef handling
• Fix TypeCastTransform missing type mappings for common PostgreSQL types
• Include PgCatalogTransform ColumnRef fix (same as Fix pg_catalog column reference and json typecast transpilation #126, for completeness)

Issues Found & Fixed

1. InformationSchemaTransform missing ColumnRef handling

Same bug pattern as #126. When information_schema.columns is rewritten to information_schema_columns_compat, column references like columns.column_name were not being updated.

-- Before: columns.column_name not rewritten
SELECT columns.column_name FROM memory.main.information_schema_columns_compat

-- After: properly rewritten
SELECT information_schema_columns_compat.column_name FROM memory.main.information_schema_columns_compat

2. TypeCastTransform missing type mappings

The following types with pg_catalog. prefix were not handled:

Type	Mapping	Notes
decimal	decimal	Strip prefix only
boolean	boolean	Strip prefix only
date	date	Strip prefix only
uuid	uuid	Strip prefix only
bit	bit	Strip prefix only
xml	varchar	Convert (DuckDB doesn't support XML)
varbit	varchar	Convert
name	varchar	Convert (PostgreSQL internal type)
oid	integer	Convert

3. PgCatalogTransform ColumnRef handling

Same fix as #126, included here since this branch is based on main.

Test plan

• Added 4 test cases for information_schema column reference rewriting
• Added 9 test cases for pg_catalog type prefix handling
• All existing tests pass

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