fix: macOS icon sizes and organize assets folder

assets/README.md

@@ -0,0 +1,34 @@
+# Assets Directory
+
+## File Structure
+
+```text
+assets/
+├── AppIcon.png              # Mac master source (1024x1024) - for icns generation & SetApp
+├── prep-icons.sh            # Generate icon.icns from AppIcon.png
+├── README.md                # This file
+│
+├── icon.icns                # Mac app icon (generated by prep-icons.sh)
+├── icon.ico                 # Windows app icon
+├── icon.png                 # Linux/Windows BrowserWindow icon (256x256)
+├── iconTemplate.png         # macOS tray icon
+├── iconTemplate@2x.png      # macOS tray icon (Retina)
+├── iconTemplate@2x.ico      # Windows tray icon (high DPI)
+│
+├── icons/                   # Linux icons ONLY (electron-builder auto-uses)
+│   ├── 16x16.png
+│   ├── 32x32.png
+│   ├── 64x64.png
+│   ├── 128x128.png
+│   ├── 256x256.png
+│   ├── 512x512.png
+│   └── 1024x1024.png
+│
+├── entitlements.mac.plist   # macOS entitlements for code signing
+├── requirement.rqset        # macOS code signing requirements
+└── assets.d.ts              # TypeScript declarations for asset imports
+```
+
+## Regenerating macOS Icons
+
+After updating `AppIcon.png`, run `prep-icons.sh`.

assets/prep-icons.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env sh
+
+# Generate icon.icns from AppIcon.png for macOS
+# This script creates a temporary iconset folder, generates all required sizes,
+# converts to icns, then cleans up.
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+SOURCE="$SCRIPT_DIR/AppIcon.png"
+OUTPUT="$SCRIPT_DIR/icon.icns"
+ICONSET="$SCRIPT_DIR/icon.iconset"
+
+if [ ! -f "$SOURCE" ]; then
+  echo "Error: Source file not found: $SOURCE"
+  exit 1
+fi
+
+echo "Generating icon.icns from AppIcon.png..."
+
+# Remove existing iconset if present
+rm -rf "$ICONSET"
+mkdir "$ICONSET"
+
+# Generate all required icon sizes for macOS
+# Format: filename - size
+# @2x variants are double the base size
+
+sips -z 16 16     "$SOURCE" --out "$ICONSET/icon_16x16.png"
+sips -z 32 32     "$SOURCE" --out "$ICONSET/icon_16x16@2x.png"
+sips -z 32 32     "$SOURCE" --out "$ICONSET/icon_32x32.png"
+sips -z 64 64     "$SOURCE" --out "$ICONSET/icon_32x32@2x.png"
+sips -z 128 128   "$SOURCE" --out "$ICONSET/icon_128x128.png"
+sips -z 256 256   "$SOURCE" --out "$ICONSET/icon_128x128@2x.png"
+sips -z 256 256   "$SOURCE" --out "$ICONSET/icon_256x256.png"
+sips -z 512 512   "$SOURCE" --out "$ICONSET/icon_256x256@2x.png"
+sips -z 512 512   "$SOURCE" --out "$ICONSET/icon_512x512.png"
+sips -z 1024 1024 "$SOURCE" --out "$ICONSET/icon_512x512@2x.png"
+
+# Convert to icns (macOS only)
+iconutil -c icns "$ICONSET" -o "$OUTPUT"
+
+# Clean up
+rm -rf "$ICONSET"
+
+echo "Successfully generated: $OUTPUT"