feat: multichain initial request+deeplinks

[elribonazo]

Explanation

This PR is adding support for mobile wallet protocol latest features (initial RPC Request) and deeplink management.

In Depth

1. DeepLinks are triggered using the old logic we had in the old SDK.
2. We integrated the initialPayload request for Mobile Wallet Protocol which speeds up connection and first request by allowing us to set an initialRPC request, which will be wallet_createSession.
3. Added better fixtures in tests that now let us test specific Web Mobile flows (deeplinks)

Right now the unitary tests are able to reproduce the following environments:

1. Desktop Browser with Extension installed
2. NodeJS platforms
3. ReactNative platforms
4. Mobile Web

References

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 highlighted breaking changes using the "BREAKING" category above as appropriate

---

Note

Adds deeplink/universal-link connection with MWP initial payload, introduces explicit Default/MWP transports, updates state/notifications and UI, and overhauls tests and playground.

• SDK Core/Transports:
  • Introduce MWPTransport (initial payload, reconnect on focus, request timeouts) and new DefaultTransport (browser extension) with session create/upgrade logic.
  • Emit stateChanged via onNotification; refactor state flow; remove getCurrentSession from MultichainCore.
  • Add deeplink connect path for secure mobile web; persist/reconnect transport; improve disconnect handling.
• UI:
  • Generate deeplink/universal link (metamask://, https://metamask.app.link); make unload/onClose async and adjust OTP modal callbacks.
• Platform/Config:
  • Add isSecure, hasExtension; new METAMASK_CONNECT_BASE_URL and METAMASK_DEEPLINK_BASE.
• Types/API:
  • Extend options (mobile.preferredOpenLink, mobile.useDeeplink, transport.onNotification); add ExtendedTransport; tweak RPC error message wording.
• Tests:
  • Replace fixtures with new tests/* harness, mocks, and envs; add web-mobile coverage; expand connect/invoke/session error scenarios.
• Playground:
  • Update React app to handle notifications/state/errors; CRACO config tweaks (conditions, polyfills).
• Dependencies:
  • Bump @metamask/mobile-wallet-protocol-* to ^0.2.x; add @types/jsdom; adjust @metamask/utils in playground.

^{Written by Cursor Bugbot for commit a3fed68. This will update automatically on new commits. Configure here.}

[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	npm/​@​metamask/​mobile-wallet-protocol-dapp-client@​0.1.1 ⏵ 0.2.1	+2			+1
	npm/​@​types/​jsdom@​21.1.7
	npm/​@​metamask/​mobile-wallet-protocol-core@​0.1.1 ⏵ 0.2.0	+2		+33	+8

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.99%. Comparing base (13cd092) to head (a3fed68).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1351      +/-   ##
==========================================
+ Coverage   74.93%   74.99%   +0.05%     
==========================================
  Files         184      184              
  Lines        4513     4519       +6     
  Branches     1105     1108       +3     
==========================================
+ Hits         3382     3389       +7     
+ Misses       1131     1130       -1     

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[chakra-guy]

We should use these two combined

https://github.com/MetaMask/mobile-wallet-protocol/pull/50/files#diff-6ad55774fe6aa232e30c073b528b62d2636a2ff63689571e9841d33bb87362caR23-R24

This will will request timeout + some grace period for the user to go back to the wallet. But the QR code will still have the same request timeout only

[chakra-guy]

So DEFAULT_REQUEST_TIMEOUT = 60s, DEFAULT_CONNECTION_TIMEOUT = 120s (DEFAULT_REQUEST_TIMEOUT + grace period for user to come back to the dapp)

[chakra-guy]

LGTM! Great tests!

[sonarqubecloud]

Quality Gate passed

Issues
27 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud