The review found the store key readable from a copy of the disk. The
desktop app only added its OS layer with the lock on, the record from
before a lock stayed in LevelDB and opened the mail with no PIN, any
frame could unwrap the PIN record and guess at it, a lock left the key
in the renderer's memory, and a store waiting after a refused login went
to whoever signed in next under the same username@host.
- The desktop app wraps the store key with safeStorage, lock or no lock.
A record without the layer gets it at its next open. A refusal is said
out loud, and only a computer with no key store goes without, which
settings say. So do they for a browser, which has no such layer.
- A record that gained layers, and every record after a changed PIN, asks
for a new key: `sqlite3_backup` into a new file under a new key while
the store keeps working, one write to the record, then the old file
goes. A changed PIN makes a new lock key, since the old PIN's record
stays on disk too. The passkey and OS unlock go with the old key.
- `wrap` and `unwrap` come through `claim()`, and the key under the PIN
takes a secret from main, one counted trip per guess.
- A lock on the desktop ends the renderer rather than reload in it.
- A sign-in compares the waiting store's JMAP account and server first,
and wipes on a mismatch. The account id keeps its form: every store,
setting and server record of an account is keyed by it.
- The 30 days also run in an app that stays open.
Changes an existing assertion: turning the lock off now keeps the
safeStorage layer, by decision, so that test expects it to stay.
