Add UTDFN-4-EP footprint and tests

[Devesh36]

Files

• Implementation: src/fn/utdfn4ep.ts
• Tests: tests/utdfn4ep.test.ts
• Snapshots: tests/__snapshots__/utdfn4ep_default.snap.svg and tests/__snapshots__/utdfn4ep_overrides.snap.svg

Summary

• utdfn4ep generates a UTDFN-4-EP footprint sized for a 1.0 × 1.0 mm body.
• Produces four symmetric side pads (pins 1–4) and a central exposed pad (EP) with ID 5.

default -

override -

/fix #183

[techmannih]

The KiCad parity test, reference text is missing in your footprint. This is not the workflow we follow for creating new footprints, and the required flag is also missing in footprinter function.