feat: implement database connection watcher

[arthurgeron]

Description

• There are situations where the DB is closed and doesn't fire a close/blocked event, so I've implemented an interval that doas a health check and attempts to restart otherwise;
• Fixes extension side DB closing until extension reload after the Vault is locked, the browser hangs for a while and other edge cases scenarios where

Note: The DB is instantiated in both the extension's main thread and the service worker, we might want to refactor to instantiate and access it only in the service worker, using Chrome's Messaging API as a communication layer with the main thread. It'd be safer and less problematic to debug than having 2 connections.

Testing:

Reproducing the Error

I'd suggest going to the Send screen (first screen after clicking send), filling out the form, waiting for the extension's lock time, then clicking send.

You can also set a debugger point in useSend.tsx in devtools, in the first line of submit function; this forces a de-sync between the extension and service worker right before the auto lock (you'll still have to wait the auto-lock time out).

Expected behavior

• Toast errors about DB connection shouldn't show continuously
• The extension should work normally after unlocking.

[github-actions]

Coverage report for ./packages/app

St.❔	Category	Percentage	Covered / Total
🟡	Statements	63.29%	3301/5216
🔴	Branches	41.58%	615/1479
🔴	Functions	47.57%	695/1461
🟡	Lines	63.88%	3184/4984

Test suite run success

246 tests passing in 73 suites.

Report generated by 🧪jest coverage report action from b2187d6