beta22 only wiped orphaned state when the lair-passphrase file itself
was missing. The Windows uninstaller turns out to be inconsistent
about which files survive — some uninstall+reinstall cycles leave
lair-passphrase + store_file behind but clear lair-keystore-config.yaml,
which our previous cleanup didn't catch. Result was the same
sqlcipher hmac crash, just from a different combination of stale files.

Check all three encryption-paired files (lair-passphrase, config,
store_file) at AppState::new. Either all three are present (working
install — reuse) or all three are absent (true fresh — generate). Any
other combination is orphaned crypto material that can't be recovered;
wipe both data dirs and start fresh.

Also surface remove_file failures in lair.rs cleanup so a future silent
permission denial doesn't masquerade as another mystery hmac crash.