Chat history not reloaded after re-authentication, causing new conversations to be invisible in UI

[pppqwe52]

Problem

After logging out and logging back in (re-authentication), new conversations created before logout are not visible in the chat history list, even though they exist in the database file.

Steps to reproduce

1. Log in to Amazon Q
2. Start a new conversation and complete it
3. Log out from Amazon Q (sign out)
4. Log back in with the same account
5. Open chat history panel
6. Observe: The conversation created in step 2 is missing from the list

Expected behavior

The chat history list should display all conversations, including those created before re-authentication. The history should be reloaded from the database when logging back in.

Actual behavior

• New conversations created before logout are not visible in the UI history list
• However, the conversations do exist in the database file (~/.aws/amazonq/history/chat-history-*.json)
• The UI only shows conversations that were already in memory from the previous session
• Workaround: Restarting VS Code forces the history to reload correctly

Log evidence:

• First login: amazonq_loadHistory telemetry event is emitted ✓
• Re-login: amazonq_loadHistory telemetry event is not emitted ✗

Root cause analysis

The issue appears to be that:

1. When logging out, the database connection is not properly closed/flushed
2. When logging back in with a new connection ID, the in-memory history index is not reloaded
3. The LSP server continues using the old in-memory index from before logout

Relevant log snippet:

13:39 First login
[2026-01-30T05:39:34.054Z] lserver: Initializing database at .../chat-history-b4dbba750d99ad0770122316d2f020bb.json
[VSCode Telemetry] Emitting amazonq_loadHistory telemetry

13:41 Re-login (after logout)
[Info - 1:41:17 PM] Runtime: Successfully saved bearer credentials
# ← No database initialization or amazonq_loadHistory telemetry!

Workaround

Restart VS Code after re-authentication to force history reload.