Score industrial fieldbus pin labels

[Mjh1231]

Summary

• Score digit-bearing industrial fieldbus labels before the generic numeric fallback.
• Preserve labels such as ETHERCAT_SYNC1 and PROFINET_RX1 in generated readable net names instead of lower-information passive hints.
• Add focused regression coverage for the fieldbus label case.

/claim #4

Tests

• bun test tests/industrial-bus-labels.test.tsx
• bun test
• bun run build
• git diff --check
• git diff --cached --check