feat: migrate braavos to the hub (reopened)

[arlert-armin]

Summary

This PR migrates Braavos to the Hub and ensures full compatibility with the updated connection and namespace architecture.
The integration required aligning Braavos’ flows with the Hub’s standardized capability and connection model. The migration was straightforward, and no limitations were identified during implementation.

Key changes:

• Migrated Braavos to use the Hub-managed connection flow.
• Ensured Starknet-related logic aligns with previously added Starknet namespace support in the core.
• Validated that all Braavos operations (connection, account fetching, signing) work correctly under the Hub orchestration.

No known limitations were found.

Fixes # (issue)

How did you test this change?

I manually tested Braavos under the Hub environment to ensure all core functionalities behave as expected:

• Verified connection flow through the Hub.

• Confirmed correct Starknet account retrieval and address handling.

• Tested signing operations to ensure compatibility.

• Test A

• Test B

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• Implemented a user interface (UI) change, referencing our Figma design to ensure pixel-perfect precision.