/claim #54

Problem

Smoothie Board DSN files contain pin definitions with modifier lists like (rotate 90) at position 2 in the AST. The existing getPinNum always read position 2, so it grabbed the modifier list instead of the actual pin number, causing the conversion to fail.

Fix

• Skip known modifier lists (rotate, mirror, flip) when extracting pin numbers
• Only coerce to number when the string is fully numeric (preserves mixed identifiers like 2@1, GND1)
• Walk AST nodes instead of hardcoding index 2

Changes

• lib/utils/get-pin-number.ts — rewritten pin extraction logic

Closes #54