Review Docs PRs for LLM Copy and x402 v2

PR #1089 on graphprotocol/docs adds "Copy page" button for LLMs, open 7 weeks. PR #1103 documents x402 v2 Payment-Signature header and payment-on-failure caveats. x402 v1's X-PAYMENT header gets 402; Payment-Signature returns 200. USDC settles on zero allocations or GraphQL errors. Both PRs await maintainer review.