ruby binding 追加

- FFI gem (libptouch)、exe ptouch-print-png（PNG のみ）
- ステータス 32 バイトを Hash に展開（parse_status / status_hash）
- CMake: libptouch 共有ライブラリ（ptouch_shared）
- RuboCop、gemspec（homepage / source_code_uri）

Made-with: Cursor

ruby/lib/libptouch.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+# Ruby FFI bindings for libptouch (Brother P-touch raster printing).
+#
+# Author: knb
+# Email: knb@artif.org
+
+require_relative "libptouch/version"
+require_relative "libptouch/error"
+require_relative "libptouch/binding"
+require_relative "libptouch/status_hash"
+require_relative "libptouch/context"
+
+module Libptouch
+  ERR_NOMEM = 1
+  ERR_ARG = 2
+  ERR_USB = 3
+  ERR_IO = 4
+  ERR_UNSUPPORTED = 5
+  ERR_NOT_FOUND = 6
+  ERR_IMAGE = 7
+
+  USB_VID_BROTHER = 0x04f9
+  USB_PID_PTP900W = 0x2085
+
+  STATUS_LENGTH = 32
+  PNG_DEFAULT_THRESHOLD = 128
+end