Restructure for multi-platform support and add Settings UI

- Move macOS code to macos/ directory for platform separation
- Add Settings window with configurable language, model path, and sound toggle
- Add launch at login support using SMAppService
- Add proper .app bundle structure with Info.plist
- Add Makefile for build, install, run, and dmg targets
- Store preferences in UserDefaults for persistence

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

macos/WhisperDictate.app/Contents/Info.plist

@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+    <key>CFBundleDevelopmentRegion</key>
+    <string>en</string>
+    <key>CFBundleExecutable</key>
+    <string>WhisperDictate</string>
+    <key>CFBundleIconFile</key>
+    <string>AppIcon</string>
+    <key>CFBundleIdentifier</key>
+    <string>com.whisperdictate.app</string>
+    <key>CFBundleInfoDictionaryVersion</key>
+    <string>6.0</string>
+    <key>CFBundleName</key>
+    <string>WhisperDictate</string>
+    <key>CFBundleDisplayName</key>
+    <string>WhisperDictate</string>
+    <key>CFBundlePackageType</key>
+    <string>APPL</string>
+    <key>CFBundleShortVersionString</key>
+    <string>1.0.0</string>
+    <key>CFBundleVersion</key>
+    <string>1</string>
+    <key>LSMinimumSystemVersion</key>
+    <string>13.0</string>
+    <key>LSUIElement</key>
+    <true/>
+    <key>NSHighResolutionCapable</key>
+    <true/>
+    <key>NSMicrophoneUsageDescription</key>
+    <string>WhisperDictate needs microphone access to record your voice for transcription.</string>
+    <key>NSAppleEventsUsageDescription</key>
+    <string>WhisperDictate needs accessibility access to paste transcribed text.</string>
+</dict>
+</plist>