Add a flag to /settings that enables the exploratory left nav. Additionally:

• Left nav
  • Create a nav item config to define the items, "active" route matches, etc.
  • Style changes
• Search
  • Bootstrapping query for loading up searchable results
  • Repair open/close behavior
  • Add keyboard shortcut
  • Repair navigation behavior
  • Style changes

View Dagit, navigate to /settings. Toggle the left nav flag, verify that the app reloads with changes.

Use search, verify that it works as intended.