feat: add docs for scaffold-hbar under /tools

[web3buidlerz]

Summary

This PR adds official documentation for Scaffold HBAR and Scaffold UI under Solutions → Developer Tools, at /solutions/tools/scaffold-hbar/.

Scaffold HBAR is the Hedera ecosystem's create-next-app-style CLI (npx create-scaffold-hbar@latest). Scaffold UI is the companion component/hook library and MCP server used by scaffolded projects and AI-assisted development. These tools are ready to document but were not yet represented in the docs portal.

What's included

Navigation (docs.json)

• New Scaffold HBAR group under Developer Tools, placed second after Developer Playground
• Pages:
  • solutions/tools/scaffold-hbar/index
  • solutions/tools/scaffold-hbar/scaffold-ui

Scaffold HBAR landing page (index.mdx)

• What Scaffold HBAR is and who it's for
• Quick start: npx create-scaffold-hbar@latest, prerequisites, non-interactive flags
• Available templates — table synced with templates/* branches (blank, hedera-demo, payments-scheduler, bridge, oracles, tokenise-subscriptions, x402-pay-per-use)
• External templates — owner/repo / owner/repo#branch usage, with featured hedera-dev/template-hedera-lz-app (LayerZero on Hedera)
• Project structure, common commands, testnet deployment
• Hedera Skills — auto-install during scaffolding, link to hedera-skills, --skip-hedera-skills option
• Links to related repos and resources

Scaffold UI page (scaffold-ui.mdx)

• Package overview (components, hooks, debug-contracts, mcp-server)
• Installation and styling
• Component docs: Address, Balance, HbarInput, HederaAddressInput
• Hook docs: useAddress, useHederaAccountId, useHederaEvmAddress, useHederaAddressInput
• Debug contracts UI and IntegerInput multipliers
• MCP server setup for Cursor, Claude Desktop, HTTP mode, and MCP Inspector

Validation

• docs.json is valid JSON
• npx mintlify broken-links — no broken links found
• Local preview via npx mintlify dev

Reviewer notes

• Template names/descriptions were sourced from hedera-dev/scaffold-hbar templates/* branches and create-scaffold-hbar CLI metadata
• LayerZero external template links to its repo README rather than duplicating deploy/runbook steps
• No redirects added (new pages only; no legacy URL moves)
• Copy / View as Markdown behavior is site-wide Mintlify config (contextual in docs.json), not per-page

Related repos

• create-scaffold-hbar — CLI
• scaffold-hbar — built-in templates
• scaffold-hbar-ui — Scaffold UI + MCP server
• template-hedera-lz-app — featured external template
• hedera-skills — auto-installed AI skills