Add Qarnot entity and Start-up Program offer

[Larslllllll]

Summary

Adds entities/qu/qarnot.yaml with one new Qarnot entity and one active startup offer.

Source

• https://qarnot.com/en/start-up

Verified: 2026-09-02. Canonical first-party page publishes:

• €6,000 in free Qarnot cloud HPC credits for the first six months
• 50% discount on computing usage (pay-as-you-go billing) after free credits expire
• Research Tax Credit (CIR) eligibility for French companies using Qarnot for R&D projects

Certification

• I change only data files (entities, taxonomy, taxRates, sourceIds)
• I cite only canonical first-party sources
• I allocate fresh IDs with the existing ent_, prg_, and off_ prefixes
• I use only the exact hosting-infra category from the taxonomy
• I checked the live catalog, all open and closed issues, and all open and closed pull requests
• I sign off commits using Signed-off-by: Name <email>

[Larslllllll]

This PR (#1261) is failing the catalog validation. I've opened a fixed version at #1268 that:

• Corrects the percentage schema on the discount benefit (using basis_points: 5000 per the n8n reference)
• Adds the missing criterion_id and updates reason to not-machine-evaluable on the manual eligibility rule
• Moves the entity file to the correct path entities/qa/qarnot.yaml

Recommend closing this PR in favor of #1268 once validated. The new PR already passes the validate-catalog-change workflow.