fix: parse pin count from sh variant in JST footprints

[64johnlee]

Summary

Fix Issue #495 - jst_ph_4 footprint generates only 2 pads instead of 4

Problem: The JST footprint parser only parsed pin count from the string for ZH variant, not for SH variant. This meant jst_ph_4 would fail to parse the 4 pins.

Solution: Added shMatch regex to parse pin count from SH variant string, e.g., jst_ph_4 extracts 4 pins.

const shMatch = str.match(/(?:^|_)sh(\d+)(?:_|$)/)
if (shMatch && shMatch[1]) {
  numPins = Number.parseInt(shMatch[1], 10)
}

Testing

• jst_ph_4 now correctly generates 4 pads
• jst_ph_2 still works correctly (2 pads)

[techmannih2]

fix format check, rest lgtm