- New credentialStore type in credentials.go loads/saves
map[id]localCred to a JSON file. Thread-safe with sync.RWMutex,
writes to disk on every mutation.
- PasskeyHandle replaces sync.RWMutex+map with *credentialStore.
Inline save/lookip/update closures delegate to store methods.
- newPasskeyHandle now takes a storePath parameter and returns an
error; callers updated.
- New -passkey-file flag (default ./passkeys.json) configures the
credential store path in main.go.
- Tests use os.CreateTemp in t.TempDir() so each test gets an
isolated, auto-cleaned store file.
kami