feat: support AGES mkII archive and audio

TODO: epk decrypt, raw PCM support

ArcFormats/aNCHOR/AudioFCD.cs

@@ -0,0 +1,55 @@
+//! \file       AudioFCD.cs
+//! \date       2026-01-19
+//! \brief      AGES Mk2 audio format.
+//
+// Copyright (C) 2026 by morkt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System;
+using System.ComponentModel.Composition;
+using System.IO;
+using System.Linq;
+
+namespace GameRes.Formats.Anchor
+{
+    [Export(typeof(AudioFormat))]
+    public class FcdAudio : AudioFormat
+    {
+        public override string         Tag { get { return "FCD"; } }
+        public override string Description { get { return "AGES Mk2 audio format"; } }
+        public override uint     Signature { get { return 0x00444346; } } // 'FCD\x00'
+
+        public FcdAudio ()
+        {
+            Extensions = new string[] { "fcd" };
+        }
+
+        public override SoundInput TryOpen (IBinaryStream file)
+        {
+            file.Position = 4;
+            // guess: big endian, version=2, type=0 (ogg), offset=0xC
+            byte[] data = { 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x4F, 0x67, 0x67, 0x53 };
+            if (!file.ReadBytes (0x0C).SequenceEqual (data))
+                throw new NotSupportedException();
+            return new OggInput (new StreamRegion (file.AsStream, 0x0C));
+        }
+    }
+}