feat: add Cyber Chief startup program record

[RanuK12]

Fixes #767. Add Cyber Chief startup program record with 75% off first year and 35% off second year offer for qualifying funded startups.

What was done

• Added vendor record for Cyber Chief (cyberchief.ai)
• Included startup program with 75% discount first year, 35% discount second year
• Used first-party sources: https://www.cyberchief.ai/p/application-security-tool-for-startups.html and https://start.cyberchief.ai/apply
• Followed repository conventions for YAML structure and ID generation

Validation

• Generated fresh ULIDs for entity_id, program_id, offer_id using node crypto
• Used single source_id for both URLs as they reference the same program
• Maintained proper YAML structure matching existing vendor records
• Added DCO sign-off to commit

/claim #767

[auscaster]

Thank you for this contribution, and apologies for the slow review.

This pull request adds a file under vendors/, which no longer exists in the repository. On 2026-08-25 authoring moved to canonical Entity records (commit ccf88f6): vendors/ was removed and entities/ became the only public data collection. The green sourcey/validation status on this branch ran before that cutover, so it certifies a schema that is no longer in use.

The change is not a path rename. The document shape moved too: an entities/ record uses schema_version: sourcey.entity-authoring/v1alpha1, nests the entity under an entity: key, and carries a separate profile: block.

I am closing this rather than leaving it in a queue it can never clear. The work is welcome and a fresh pull request against entities/ stands a good chance:

• place the file at entities/{first two characters of the slug}/{slug}.yaml
• copy the shape of a nearby record in entities/ and follow CONTRIBUTING.md
• cite only canonical sources: pages on the vendor's own domain, or on the domain of an entity named in the offer's roles
• sign off your commits with git commit --signoff

Before starting, please check the open pull requests so two people do not write the same record.

One thing to correct when you re-submit: sourcey/validation is failing.

_{Reviewed by hand against CONTRIBUTING.md and the canonical-source rule, 28 Aug 2026.}