data: add Twelve Data startup program

[yunaremaia]

Summary

Adds one new vendor, Twelve Data (vendors/tw/twelve-data.yaml), with the vendor-run Twelve Data for Startups program: API plans designed and priced for early-stage company budgets on its financial market data platform.

Reservation issue: #743

Facts and sourcing

All facts are taken from the single first-party source cited in the record:

• https://twelvedata.com/startups (verified live today)

Published facts captured in structured fields:

• Benefit: "Access robust APIs with a plan of your choice, at a price that fits your budget" ("Designed and priced for startups") → kind: other benefit; no percentage or dollar figure is published, so consideration stays unknown
• Eligibility, from the page's three stated requirements:
  • "Early stage: Up to $1M in funding and less than 2 years old" → company.funding_raised_usd lte 1,000,000 and company.age_years lt 2 (machine-evaluable predicates)
  • "Single structure: Legal entity and same use as domain" → manual rule (not-machine-evaluable)
  • "Small team: 10 employees or less" → company.employee_count lte 10
• Access: public application through the vendor's own perks form, linked as "Apply now" from the program page → https://twelvedata.com/account/perks/2

No amounts beyond what the page states. No dollar figure was invented for the plan pricing.

Checklist

• Data-only PR: exactly one new vendor YAML under vendors/{shard}/ (shard tw from slug twelve-data)
• Fresh ULIDs generated per CONTRIBUTING (ent_, prg_, off_, opaque src_)
• Category from the pinned verifier taxonomy: data-analytics
• Local preflight run with the digest-pinned Catalog Verifier: {"status":"valid","vendors":1,"programs":1,"offers":1}
• DCO sign-off present on the commit
• Vendor not present in catalog; searched open issues/PRs before starting (reservation Reservation: Twelve Data Early Stage Program #743)