Score power bus pin labels

[Mjh1231]

Summary

• Score digit-bearing power-management bus labels before the generic numeric fallback.
• Preserve labels such as PMBUS_ALERT1 and SMBUS_SCL1 in generated readable net names instead of lower-information passive hints.
• Add focused regression coverage for the power-bus label case.

/claim #4

Tests

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