Ralph/camelcase refactoring

[ryogrid]

This pull request primarily refactors the catalog-related code for improved clarity and consistency, focusing on renaming variables and constants to follow Go naming conventions and updating usages across the codebase. It also fixes some minor issues with constant usage and plugin settings.

Refactoring for naming consistency:

• Renamed various identifiers in lib/catalog/table_catalog.go to use Go-style capitalization and naming conventions, such as TableCatalogPageId → TableCatalogPageID, tableIds → tableIDs, and log_manager → LogManager. This applies to struct fields, constants, variables, and function arguments throughout the file. [1] [2]
• Updated usages of renamed constants and variables in catalog schema definitions and test files, such as INDEX_KIND_INVALID → IndexKindInvalid and indexHeaderPageId → indexHeaderPageID. [1] [2] [3]

Code clarity and function argument improvements:

• Changed function argument names from generic (e.g., schema_) to more descriptive (sc) in catalog and statistics code, and updated all usages accordingly. [1] [2]

Bug fixes and correctness:

• Fixed usage of expression type constants in statistics code to use the correct enum values (e.g., EXPRESSION_TYPE_COMPARISON → ExpressionTypeComparison). [1] [2] [3]
• Corrected variable naming in statistics methods for column index arguments (e.g., col_idx → colIdx).

Plugin configuration:

• Added a .claude/settings.json file to enable the ralph-skills@ralph-marketplace plugin.