Reverify docs and skill against current merged truth

[JimCollinson]

Summary

• reverify the docs set against the latest upstream heads across ant-sdk, ant-client, ant-node, evmlib, ant-protocol, saorsa-core, saorsa-pqc, and saorsa-transport
• fix current-main doc drift in CLI, Rust, SDK, MCP, payment, and local-devnet guidance
• refresh the merged start skill package so its verification metadata and troubleshooting guidance match the latest merged behavior

What changed

• refreshed verification SHAs and dates across the affected docs pages
• corrected SDK and MCP discovery guidance using the current upstream daemon.port writer/reader implementations
• updated CLI docs for current root-flag behavior, file cost, and private download output rules
• updated Rust docs for devnet feature gating, wallet-backed paid-write examples, and the current ant-node crate version
• updated payment and external-signer docs for current helper coverage and clearer write prerequisites
• refreshed the merged skill package metadata and guidance under skills/start/

Validation

• git diff --check
• skill package consistency check across SKILL.md, version.json, and CHANGELOG.md
• direct upstream verification of disputed SDK/MCP behavior using raw GitHub source files
• focused content review for CLI, Rust, SDK, MCP, payment, and skill guidance

Supersedes

• supersedes Reverify docs and skill against current merged truth #15, which was cut before the latest main updates and is now conflicted