Desktop client gets into a state where it cannot sync chat messages any more

Repro steps:

1. Install Windows desktop client
2. Chat with some people
3. Close my laptop screen, which disconnects WiFi and puts Windows into "sleep" or "hibernation" mode
4. Restart Windows and connect to WiFi again

**Expected:** Chat resyncs properly
**Actual:** Keybase shows "Digging ancient messages" screen, and is permanently stuck, unable to sync any new messages.

## This did NOT fix the problem:

1. Exit the Keybase client
2. Run "KeyBase.exe db nuke"
3. Restart the Keybase client

**Result:** All the chat history is cleared, but syncing is still broken.

## This DOES fix the problem:

1. Exit the Keybase client
2. Run "KeyBase.exe db nuke"
3. Uninstall the KeyBase client
4. Run the installer again to reinstall Keybase
5. Restart the Keybase client

Lately I've been getting into this broken state at least once per week.

**QUESTION:** What does uninstalling do, that `keybase db nuke` does NOT do?

Start by reproducing the Windows desktop client's failure after WiFi disconnect and sleep or hibernation, then compare `KeyBase.exe db nuke` with uninstalling and reinstalling. Trace which state survives the database reset and verify that the client can resync chat messages afterward without requiring reinstallation.

Written by the indexing model from the issue text.