feat(promo): add new self-service promo code

[jobrietbergen]

Summary

• Adds a new encrypted self-service promotional credit entry.

Verification

• Typecheck passed.

Visual Changes

N/A

Reviewer Notes

N/A

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (1 files)

• apps/web/src/lib/promoCreditCategories.ts

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_{Reviewed by gpt-5.4-20260305 · 359,848 tokens}