fix: recognize MetaMask Flask (io.metamask.flask) as native MetaMask

[adonesky1]

Explanation

MetaMask Connect only treated io.metamask (production extension) and io.metamask.mobile as native MetaMask EIP-6963 providers. MetaMask Flask announces itself with rdns: 'io.metamask.flask', which was missing from every allowlist. As a result hasExtension() returned false when only Flask was installed, so MetaMaskConnectMultichain.connect() fell through to the MWP transport (QR code / mobile deeplink) instead of using the locally-installed Flask extension — even though the browser postMessage transport (metamask-contentscript) works with Flask just fine. The legacy @metamask/sdk recognized Flask (METAMASK_EIP_6369_PROVIDER_INFO.RDNS = ['io.metamask', 'io.metamask.flask']), so to consumers this looked like a regression.

This surfaced during a live-stream dApp build that migrated to MetaMask Connect + wagmi while using Flask: the connection only worked after manually selecting wagmi's auto-discovered io.metamask.flask connector, which bypasses the Connect SDK entirely.

What changed

Primary fix — add io.metamask.flask to the recognized native MetaMask RDNS values in the three places that gate Flask:

• packages/connect-multichain/src/domain/platform/index.ts — NATIVE_METAMASK_EIP6963_RDNS (drives hasExtension(), which selects the extension vs MWP transport).
• packages/connect-evm/src/eip6963.ts — METAMASK_EIP6963_RDNS (announce-suppression so the SDK doesn't announce a duplicate MetaMask entry alongside Flask).
• integrations/wagmi/metamask-connector.ts — the metaMask() connector's rdns (plus the two playground copies for parity).

Docs (nice-to-have) — the metamask-connect skill never mentioned Flask. Added a troubleshooting entry, updated the wagmi setup/migration notes, and fixed related doc comments + the connect-evm README.

Result

With only Flask installed on desktop web, the Connect connector now uses the browser extension transport (no QR/MWP fallback) and connects like the production extension.

References

• WAPI-1559
• Legacy behavior: @metamask/sdk packages/sdk/src/constants.ts (METAMASK_EIP_6369_PROVIDER_INFO.RDNS)

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed, highlighting breaking changes as necessary
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes