Add DROP TABLE and CREATE TABLE (DDL) formatting

[kinnell]

Description

This PR serves to add formatting support for DROP TABLE and CREATE TABLE DDL statements, and fix single-column INSERT rendering.

Previously, DROP TABLE and CREATE TABLE (with column definitions) statements were not recognized by any parser and fell through to the normalized-text passthrough. They now get proper keyword casing and PascalCase table names, consistent with the rest of the formatter.

The CREATE TABLE parser supports modifiers (TEMP, TEMPORARY, UNLOGGED, LOCAL) and IF NOT EXISTS, preserving column definitions as-is. The modifier constant previously defined in CreateTableAs has been extracted to Constants::TABLE_MODIFIERS so both parsers can share it.

A small fix to InsertQuery#render_column_list ensures single-column lists render inline (e.g., insert into Table (id)) instead of expanding to three lines.

[Copilot]

Pull request overview

Adds first-class formatting support for basic DDL statements (DROP TABLE, CREATE TABLE with column definitions) so they no longer fall back to normalized-text passthrough, and fixes single-column INSERT column-list rendering to stay inline.

Changes:

• Add SqlBeautifier::DropTable and SqlBeautifier::CreateTable parsers/renderers and integrate them into Formatter.
• Centralize CREATE TABLE modifier keywords in Constants::TABLE_MODIFIERS (shared by CreateTableAs and CreateTable).
• Fix InsertQuery#render_column_list to render single-column lists inline and expand tests/docs accordingly.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
spec/sql_beautifier/insert_query.spec.rb	Adds coverage for inline single-column INSERT column lists and updates existing expectations.
spec/sql_beautifier/formatter.spec.rb	Integration coverage for DROP TABLE / CREATE TABLE and single-column INSERT through the main formatter.
spec/sql_beautifier/drop_table.spec.rb	New unit specs for DROP TABLE parsing/rendering and configuration interactions.
spec/sql_beautifier/create_table.spec.rb	New unit specs for CREATE TABLE (DDL) parsing/rendering and configuration interactions.
spec/sql_beautifier.spec.rb	Verifies multi-statement formatting across DROP/CREATE/INSERT sequences.
spec/readme.spec.rb	Adds/updates README example expectations, including new DDL examples.
lib/sql_beautifier/insert_query.rb	Implements inline rendering for single-column column lists.
lib/sql_beautifier/formatter.rb	Routes DROP TABLE and CREATE TABLE statements to their new formatters.
lib/sql_beautifier/drop_table.rb	Introduces DROP TABLE parser/renderer.
lib/sql_beautifier/create_table_as.rb	Switches modifier detection to shared Constants::TABLE_MODIFIERS.
lib/sql_beautifier/create_table.rb	Introduces CREATE TABLE (DDL) parser/renderer for column-definition form.
lib/sql_beautifier/constants.rb	Adds TABLE_MODIFIERS shared constant.
lib/sql_beautifier.rb	Requires the new DropTable/CreateTable implementations.
README.md	Documents new DROP TABLE / CREATE TABLE formatting support with examples.
CHANGELOG.md	Records the new DDL formatting support and the INSERT single-column rendering fix.

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