Announce Nano (XNO) availability across documentation and templates

[cbrunnkvist]

I was a bit too focused on the technical side in #109, and left out a fair chunk of "end-user discoverability" by failing to mention the chain in all (more than I expected) the different places where we mention builtin support for x y and z.

This PR ensures that Nano/XNO/nano_ are consistently listed alongside other supported chains, what standard derivation paths are used, etc. There are also some code samples updated accordingly...

Mostly, I found mentions in...:

• per-language README.md files
• chain summary tables here and there
• examples and "Usage:" references
• TypeScript and Python code sample output
• the quickstart snippets and getting started guides now mention Nano as part of the default supported chains
• Crate-level files also reflect Nano support

In short, we ensure that developers, users and Googlebots alike can discover that Nano is now a supported chain in the OWS ecosystem 👍

Testing

• cargo test --workspace passes
• cargo clippy --workspace -- -D warnings is clean
• npm test passes (if Node bindings changed)
• Tested manually with ows CLI

Notes

There is already a companion-utility that bundles a set of Nano-transacting Agent skills 🦀 at @casualsecurityinc/xno-skills now built directly on top of the OWS 🥳 (but I think it is outside of the scope of these OWS documents to mention 3rd party tooling in the docs)

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Note

Low Risk
Documentation-only updates that list Nano as a supported chain; no runtime logic changes, so risk is limited to potential docs inconsistencies.

Overview
Adds Nano (XNO) to the documented supported-chain set across the main README, Node/Python binding READMEs, crate READMEs, and generated readme templates/partials.

Updates chain tables and examples to include Nano-specific details (coin type 165, derivation path m/44'/165'/0', nano_ address prefix), and extends docs/07-supported-chains.md with nano:mainnet and alias/HD-derivation references; quickstart text is also updated to mention Nano in the default chain set.

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[cbrunnkvist]

Uh, also please let me know if completely overlooked how perhaps some docs-amending agent maybe is supposed do do this authoring in some semi-auto fashion?! I.e. am I even doing the right thing here?