feat: move x402 payment skill to CLI GasFree workflow

[boboliu-1010]

Summary

• replace skill-local TypeScript payment scripts with x402-cli commands
• require canonical TRON CAIP-2 network identifiers
• document safe dry-run, amount limits, and GasFree relayer fee limits
• install and verify @bankofai/x402-cli@1.0.1-beta.7, built with released x402 SDK 1.0.1
• preserve existing installation state and clean temporary installer files
• update agent-wallet TRON network examples

Release

• skill tag: x402-payment-v1.0.1-beta.8
• full repository tag: v1.5.15-beta.3
• CLI dependency: @bankofai/x402-cli@1.0.1-beta.7

Validation

• install.sh and uninstall.sh shell syntax
• installer dry-run verifies beta.7
• isolated installation from v1.5.15-beta.3 installed the published CLI and skill
• x402-cli --version returned 1.0.1-beta.7

Notes

• payments must use both an amount cap and a GasFree fee cap.
• SunPump upstream HTTP 405 is not handled by this skill change.