Add PDIP-8 footprint alias

[DrOetker747]

/claim #371

Adds PDIP string normalization for the existing DIP footprint generator so common package names such as PDIP-8, pdip8, and parameterized forms like pdip8_w7.62mm resolve through the same implementation as dip8.

This keeps the footprint geometry in one place instead of duplicating the DIP generator for the plastic DIP naming variant.

Verification run locally:

• npm exec -- biome check src/footprinter.ts tests/dip.test.ts
• npm run build
• direct Node check against the built package confirming PDIP-8 and pdip8 produce the same JSON as dip8
• git diff --check

Notes:

• The repo expects bun test, but bun is not installed in this environment, so I could not run the Bun test suite directly.
• npm exec -- tsc --noEmit currently reports unrelated pre-existing type errors in several test files involving circuit-json union types; npm run build succeeds for the package source and declarations.