CIP-0146 Wallet Discovery, Expanded Playwright Coverage and CI Improvements

[Andre-Diamond]

Wallet Discovery and Import Improvements

• Add a Discover tab for the CIP-0146 wallet import flow.
• Add stake key and DRep key recovery during wallet import.
• Add base-address recovery for co-signers and improve address assignment.
• Add an advanced signer address-adjustment option to the import flow.

Expanded Playwright Browser Coverage

• Add browser tests for transaction recipient and amount validation.
• Add notification settings tests covering email preferences and persistence.
• Add proxy management UI tests.
• Add tests for rejected wallet signing during transaction proposals and approvals.
• Add responsive smoke tests for critical screens and mobile viewports.
• Add staking UI tests covering actions for different account states.
• Add wallet access-control tests for protected wallet pages.
• Add and update the Playwright test plan and local-running documentation.

CI and Browser-Test Reliability

• Add support for parallel branches in proxy lifecycle scenarios.
• Update Playwright Docker images and required CI secrets.
• Improve proxy proposal caching in CI scenarios.
• Improve handling of rate-limit responses in signing flows.
• Improve wallet navigation and retry handling in browser tests.
• Increase Playwright expectation timeouts to support cold application loads.