Lightweight Query Builder

[CodeMaverick-143]

Writing raw SQL is error-prone, but full ORMs (like TypeORM) are too heavy for this framework.

Technical Implementation:

• Create a fluent API for constructing SQL queries (e.g., db.select('*').from('users').where('id', 1)).
• Support parameter binding to prevent SQL injection.
• Adapters for pg, mysql2, and better-sqlite3.

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Acceptance Criteria:

• A query built with the builder executes safely against a SQLite database.
• SQL injection attempts via input parameters are neutralized.