Correct live x402 evidence claims

[mizuki0x]

Summary

• remove identity-passport and settlement-grounded-reputation claims from the public x402 documentation
• describe registration and transfer data as bounded observations rather than proof
• state the current outbound payment path’s recipient, endpoint, accounting, and settlement limitations
• separate resource delivery from payment settlement

The currently deployed docs overstate what the implementation can prove. This patch is intentionally documentation-only so the correction can ship before the larger hardening work.

Validation

• git diff --check
• tsc --noEmit -p landing/tsconfig.json