docs: add security and polkadot chain support pages

[devin-ai-integration]

docs: add security and polkadot chain support pages

Summary

Adds two new documentation pages to the Wallet SDK section, migrated and adapted from the Reown Docs where they previously lived as WalletKit-related content:

1. Security Information (wallet-sdk/security.mdx) — Covers Wallet SDK architecture, end-to-end encryption, Trail of Bits / Spearbit audits, dependency philosophy, and bug bounty info. Adapted from the Reown security page with AppKit-specific content removed.

2. Polkadot RPC Reference (wallet-sdk/chain-support/polkadot.mdx) — Documents the polkadot_signTransaction and polkadot_signMessage JSON-RPC methods, following the same RPC reference format used by the other chain-support pages (EVM, Solana, Bitcoin, etc.). Sourced from the Reown Polkadot RPC reference.

Navigation updated in docs.json:

• Polkadot added to the "Chain Support" group alongside EVM, Solana, Bitcoin, etc.
• New "Security" group added between WalletGuide and Production sections.

Note: The Reown docs-writing-skill page (page 9 from the original audit) was not added since this repo already has its own docs-writing-skill.md.

Updates since last revision

• Replaced the full Polkadot WalletKit integration guide + namespaces guide with a Polkadot RPC reference page, per review feedback from @jakubuid. The chain-support section should contain only RPC references, matching the existing docs structure.

Local Testing

Security page verified locally with mint dev:

Mintlify preview deployment: https://test-walletconnect-devin-1770734940-add-walletkit-pages.mintlify.app

Review & Testing Checklist for Human

• Verify Mintlify components render correctly — The Polkadot page uses <Warning> and <Note> components. Confirm these render properly in the preview deployment.
• Check <Bytes> tags render as literal text — The polkadot_signMessage security warning mentions wrapping messages in <Bytes>message</Bytes> tags. Verify this renders as literal text, not as a component.
• Verify external links — The security page links to walletconnect.network/security for bug bounty and contact. Confirm this URL resolves correctly.
• Check the Mintlify preview deployment — Confirm both pages render properly, navigation works, and code blocks display correctly.

Recommended test plan:

1. Open the preview deployment and navigate to both new pages via the sidebar
2. Verify the Polkadot page warning banner and note component render correctly
3. Click all external links to confirm they resolve

Notes

• This PR is part of a larger effort to migrate WalletKit documentation from Reown Docs to WalletConnect Docs.
• Requested by Jem Conlon
• Link to Devin run

[devin-ai-integration]

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[Sam-Newman]

@jakubuid Please can you review this?

Its more your expertise! :)

[jakubuid]

What's the reason behind adding full integration guide for WalletKit here not just Poladot RPC reference as here?
https://docs.reown.com/advanced/multichain/rpc-reference/polkadot-rpc

WalletKit integration guides can be found here for all the platforms: https://test-walletconnect-devin-1770734940-add-walletkit-pages.mintlify.app/wallet-sdk/overview

chain-support section should keep just the RCP reference, following current docs structure

[devin-ai-integration]

Good catch — you're right, the chain-support section should follow the RPC reference pattern like the other chains. I've replaced the full integration guide with the Polkadot RPC reference content (polkadot_signTransaction and polkadot_signMessage) matching the structure of the existing EVM, Solana, etc. pages. See commit a35967d.