Multi-bridge Phase 1.3: Bridge switcher in toolbar

[tashda]

Why

Once multiple bridges are saved (#1.1, #1.2), switching between them needs to be one tap, not three taps via Settings. The switcher is the primary daily-use UX for users who run more than one Z2M instance.

What

• New shared component Shellbee/Shared/Components/BridgeSwitcherToolbarItem.swift:
  • Shows the active bridge's displayName plus a chevron.
  • Tap → menu listing all saved bridges with a checkmark on the active one.
  • Selecting another bridge calls environment.connect(config:) (which already calls session.disconnect() + store.reset() internally — but see Implement stateful Z2M engine and enhance UI test coverage #1.7 for connect-failure UX).
  • Hide the switcher entirely if there's only one saved bridge (avoid clutter for single-bridge users).
  • Show a brief inline progress indicator while reconnecting (read connectionState from ConnectionSessionController).
• Wire into the toolbar of:
  • Shellbee/Features/Home/HomeView.swift
  • Shellbee/Features/Devices/DeviceListView.swift
  • Shellbee/Features/Groups/GroupListView.swift
  • Shellbee/Features/Logs/LogsView.swift

Files

• New: Shellbee/Shared/Components/BridgeSwitcherToolbarItem.swift
• Edit toolbars: HomeView.swift, DeviceListView.swift, GroupListView.swift, LogsView.swift
• Add new file to membershipExceptions if it imports AppEnvironment.

Verification

• Use Implement stateful Z2M engine and enhance UI test coverage #1.6's dual-seeder docker setup. Save both bridges. Confirm the switcher appears in all 4 top-level views.
• Switch back and forth — devices/groups/logs swap cleanly. Any zombie state from the previous bridge bleeding through is a AppStore.reset() bug to be fixed by Implement stateful Z2M engine and enhance UI test coverage #1.4.
• Switch with only one saved bridge — switcher is hidden.

Phase

Phase 1 of multi-bridge support. Depends on #1.1, #1.2.

[tashda]

Implemented in c33b04c (Add bridge switcher toolbar item to top-level views).