fix: post-emulator regressions

[re1sub]

Summary

1. Fixes a regression where created collections didn't appear in the sidebar for service account and emulator projects (required manual "Refresh Collections"). Root cause: fire-and-forget dispatch(refreshCollections) in createCollection silently swallowed errors.
2. Created collections not appearing at all for emulators: refreshCollections.fulfilled reducer was missing emulator auth method.
3. Hide "Add database" UI for emulator projects (emulator doesn't support named databases).

• Fix refreshCollections.fulfilled reducer to handle emulator auth method
• Disable "Add database" toolbar buttons and context menu item for emulator projects
• Await refreshCollections dispatch in createCollection thunk so errors aren't silently swallowed

Test plan

• Create a collection via service account project — sidebar updates immediately
• Create a collection via emulator project — sidebar updates immediately
• "Add database" buttons are hidden for emulator projects
• "Add database" context menu item is hidden for emulator projects