data: add Routine for Startups

[nwinkelman2]

Summary

• add one new Routine entity and one startup-specific offer
• record the canonical one-year free Routine Business benefit and the first-party up-to-USD-2,500 qualifier
• preserve the published non-paying-customer, team-size, funding, company-domain, and corporate-status eligibility constraints

Evidence

• First-party program and terms: https://routine.co/partnerships/startups
• Missing-record issue: Missing startup offer: Routine for Startups #1252

Validation

• YAML parses successfully
• exactly one new Entity file
• no existing Routine catalog entity, Sourcey issue, or Sourcey PR was present when reserved
• git diff --check passes

Closes #1252