refactor: sync and login errors

[CiTroNaK]

What?

Improves sync error handling and reporting for malformed Proton Pass items and logged-out CLI sessions.

Why?

A single malformed item could break the whole sync, and sync/auth failures were hard to understand or act on from the main window.

How?

• Parse item lists lossily during sync, skipping malformed items while syncing valid ones.
• Show richer sync progress and skipped-item status.
• Add skipped-item details with sanitized summaries plus Copy Report / Copy & Report.
• Add friendly sync error UI:
  • "Log In" for auth errors
  • "Copy & Report" for fatal sync errors
• Keep diagnostics sanitized and report via email
• Update login-required state immediately from Pass CLI health changes.