Add FT-991A Remote Control App for macOS

Complete Phase 1 implementation of the Yaesu FT-991A remote control
application with CAT protocol support over USB serial (CP210x).

Features implemented:
- SerialPortManager with auto-detection of CP210x ports
- Full CAT protocol parser and command builder
- RadioState model with all transceiver parameters
- Modern SwiftUI interface with frequency/mode/level controls
- Skeuomorphic front panel view (switchable)
- Debug panel with CAT command console
- QSO log panel with CSV export/import
- Audio routing panel with BlackHole integration
- Settings with connection, UI, keyboard configuration
- Menu bar extra for background operation
- German/English localization
- Logging system for debugging

Supports: Frequency control, VFO A/B, all modes (LSB/USB/CW/FM/AM/
DATA/RTTY/C4FM), level controls, NB/NR/DNF/ATU/Split functions,
S-meter/Power/SWR metering, PTT control via Shift key.

Target: macOS 15.0+ (Sequoia/Tahoe)

FT991A-Remote/FT991A-Remote/Assets.xcassets/AccentColor.colorset/Contents.json

@@ -0,0 +1,38 @@
+{
+  "colors" : [
+    {
+      "color" : {
+        "color-space" : "srgb",
+        "components" : {
+          "alpha" : "1.000",
+          "blue" : "0.984",
+          "green" : "0.584",
+          "red" : "0.000"
+        }
+      },
+      "idiom" : "universal"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "color" : {
+        "color-space" : "srgb",
+        "components" : {
+          "alpha" : "1.000",
+          "blue" : "1.000",
+          "green" : "0.678",
+          "red" : "0.251"
+        }
+      },
+      "idiom" : "universal"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

FT991A-Remote/FT991A-Remote/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -0,0 +1,58 @@
+{
+  "images" : [
+    {
+      "idiom" : "mac",
+      "scale" : "1x",
+      "size" : "16x16"
+    },
+    {
+      "idiom" : "mac",
+      "scale" : "2x",
+      "size" : "16x16"
+    },
+    {
+      "idiom" : "mac",
+      "scale" : "1x",
+      "size" : "32x32"
+    },
+    {
+      "idiom" : "mac",
+      "scale" : "2x",
+      "size" : "32x32"
+    },
+    {
+      "idiom" : "mac",
+      "scale" : "1x",
+      "size" : "128x128"
+    },
+    {
+      "idiom" : "mac",
+      "scale" : "2x",
+      "size" : "128x128"
+    },
+    {
+      "idiom" : "mac",
+      "scale" : "1x",
+      "size" : "256x256"
+    },
+    {
+      "idiom" : "mac",
+      "scale" : "2x",
+      "size" : "256x256"
+    },
+    {
+      "idiom" : "mac",
+      "scale" : "1x",
+      "size" : "512x512"
+    },
+    {
+      "idiom" : "mac",
+      "scale" : "2x",
+      "size" : "512x512"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

FT991A-Remote/FT991A-Remote/Assets.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}