data: add Deskwoot startup program

[epistemedeus]

What changed

Adds one new Deskwoot vendor record with its named Startup Program and one offer: six months of Enterprise access for 10 agent seats at no charge.

Closes #205.

Sources

• https://deskwoot.com/startups

Certification

• I changed only allowed repository content and did not mix vendor YAML with other paths.
• Public sources substantiate every submitted factual value; any Sourcey-written prose is a neutral summary, not a fabricated vendor quote.
• I did not author verification, provenance, freshness, or signature claims.
• My commits include a Signed-off-by line.