Add Penny Press

[con-scribe]

Adds Penny Press to the Niche & Specialty shelf: original essays on freedom, economics and philosophy — free for humans, pay-per-read for machines via x402 micropayments in USDC on Base mainnet. The linked /.well-known/x402 manifest answers live 402 challenges for every endpoint.

[github-actions]

Gold-402 Verification: PASSED

URL checked: https://www.pennypress.org/.well-known/x402 (link in the entry line this PR adds)
Rule applied: service -- must answer HTTP 402
Result: manifest at https://www.pennypress.org/.well-known/x402 declares 44 resource(s); https://www.pennypress.org/essays/full answered HTTP 402 -- x402 compliant

This PR has been approved for merge. A maintainer will review and merge shortly.

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Verified by Gold-402. Verification confirms x402 technical compliance only. It does not constitute endorsement of the service.

[Haustorium12]

Knocked live 2026-10-04: GET /essays/full → 402 at $0.20 and a single piece at $0.01, both on Base. Your manifest lists 49 resources at $0.01–$0.25 and the line had no price, so I added "$0.01–$0.25 per read" on merge. Thanks.