Initial implementation of arca, a LUKS volume manager.

Go CLI using cobra with mount, unmount, status, and init subcommands.
Unlocks via udisks2 D-Bus (passphrase/keyfile) or cryptsetup (FIDO2/TPM2)
with ordered method fallback. Includes NixOS-specific LD_LIBRARY_PATH
injection for systemd cryptsetup token plugins.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/udisks/types.go

@@ -0,0 +1,27 @@
+package udisks
+
+import "github.com/godbus/dbus/v5"
+
+const (
+	busName      = "org.freedesktop.UDisks2"
+	objectPrefix = "/org/freedesktop/UDisks2"
+
+	ifaceObjectManager = "org.freedesktop.DBus.ObjectManager"
+	ifaceBlock         = "org.freedesktop.UDisks2.Block"
+	ifaceEncrypted     = "org.freedesktop.UDisks2.Encrypted"
+	ifaceFilesystem    = "org.freedesktop.UDisks2.Filesystem"
+)
+
+// BlockDevice represents a udisks2 block device.
+type BlockDevice struct {
+	ObjectPath          dbus.ObjectPath
+	DevicePath          string // e.g., "/dev/sda1"
+	UUID                string
+	HasEncrypted        bool
+	HasFilesystem       bool
+	CryptoBackingDevice dbus.ObjectPath
+}
+
+func noOptions() map[string]dbus.Variant {
+	return make(map[string]dbus.Variant)
+}