Implement `CREATE TABLE` Parser

[stifskere]

Sub-issue of #3

Objective

Parse CREATE TABLE SQL statements and extract schema info, starting with PostgreSQL dialect.

Tasks

Stage 1: PostgreSQL CREATE TABLE (priority)

• Tokenize and parse PostgreSQL CREATE TABLE syntax.
• Extract table name, columns, and constraints.
• Output intermediate representation usable by AST builder.

Stage 2: Full MVP / Other Dialects

• Extend parser to MySQL, MariaDB, SQLite syntax variants.
• Handle complex constraints, indexes, and extended column types.

Note: No Stage 1 for other dialects; prioritize Stage 1 PostgreSQL parser first

[stifskere]

Assigned stage 1 to @chikof, to contribute to the stage 1, please mention him.