feat: support integer formatting in printf

[viveknathani]

Description

Adds width specifier support for %d and %i format specifiers in the printf function. This continues the support for the issue #885.

Examples:

• Width specifiers: printf('%5d', 42) → " 42" (right-padded to 5 characters)
• Zero-padding: printf('%05d', 42) → "00042" (zero-padded instead of spaces)
• Precision: printf('%.3d', 42) → "042" (minimum digits)
• Combined: printf('%5.3d', 42) → " 042" (width + precision together)

Behavior matches SQLite's printf implementation.

Motivation and context

I got interested in contributing and I saw in COMPAT.md that printf needs better support for modifiers. This felt like a good first contribution to make. It aligns with the goal of making Turso compatible with SQLite.

Description of AI Usage

Claude code helped me with a code review. It suggested eliminating code duplication by parsing width separately from format type handling.

[turso-bot]

Please review @pereman2

[viveknathani]

hi @pereman2 - quick ping, would appreciate your thoughts when you get a chance.