Add Konverter: a local-only menu bar file converter

Drag files in Finder, hold a modifier, and drop on a wheel of outputs.
Conversions run entirely on-device through ImageIO, PDFKit, AVFoundation,
the bundled CLI tools, and optional ffmpeg/LibreOffice.

Includes a --self-test suite (41 checks) and a --convert CLI mode so the
conversion matrix can be verified without the UI.

build-app.sh

@@ -0,0 +1,112 @@
+#!/bin/bash
+# Builds Konverter.app.
+#
+#   ./build-app.sh            # version from git tag, else 0.1.0
+#   ./build-app.sh 1.2.0      # explicit version
+#
+# Signs with the first Developer ID Application identity in the keychain when
+# one exists (needed for notarization), otherwise ad-hoc signs so the bundle
+# still runs locally.
+set -euo pipefail
+cd "$(dirname "$0")"
+
+if [ "${1:-}" != "" ]; then
+    VERSION="$1"
+else
+    VERSION=$(git describe --tags --abbrev=0 2>/dev/null | sed 's/^v//' || true)
+    VERSION="${VERSION:-0.1.0}"
+fi
+
+swift build -c release
+
+BIN=".build/release/Konverter"
+APP="Konverter.app"
+
+if [ ! -x "$BIN" ]; then
+    echo "build-app.sh: $BIN not found after swift build." >&2
+    exit 1
+fi
+
+IDENT=""
+if command -v security >/dev/null 2>&1; then
+    IDENT=$(security find-identity -v -p codesigning 2>/dev/null \
+        | awk '/Developer ID Application:/ { print $2; exit }')
+fi
+
+rm -rf "$APP"
+mkdir -p "$APP/Contents/MacOS" "$APP/Contents/Resources"
+cp "$BIN" "$APP/Contents/MacOS/Konverter"
+printf 'APPL????' > "$APP/Contents/PkgInfo"
+
+cat > "$APP/Contents/Info.plist" <<PLIST
+<?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>Konverter</string>
+    <key>CFBundleIconFile</key>
+    <string>Icon</string>
+    <key>CFBundleIdentifier</key>
+    <string>dev.tzgyn.konverter</string>
+    <key>CFBundleInfoDictionaryVersion</key>
+    <string>6.0</string>
+    <key>CFBundleName</key>
+    <string>Konverter</string>
+    <key>CFBundleDisplayName</key>
+    <string>Konverter</string>
+    <key>CFBundlePackageType</key>
+    <string>APPL</string>
+    <key>CFBundleShortVersionString</key>
+    <string>${VERSION}</string>
+    <key>CFBundleVersion</key>
+    <string>${VERSION}</string>
+    <key>LSMinimumSystemVersion</key>
+    <string>13.0</string>
+    <key>LSUIElement</key>
+    <true/>
+    <key>LSApplicationCategoryType</key>
+    <string>public.app-category.utilities</string>
+    <key>NSHighResolutionCapable</key>
+    <true/>
+    <key>NSPrincipalClass</key>
+    <string>NSApplication</string>
+    <key>NSHumanReadableCopyright</key>
+    <string>Copyright © 2026 Teh Zi Gyn. All rights reserved.</string>
+    <key>NSServices</key>
+    <array>
+        <dict>
+            <key>NSMenuItem</key>
+            <dict>
+                <key>default</key>
+                <string>Convert with Konverter…</string>
+            </dict>
+            <key>NSMessage</key>
+            <string>convertFiles</string>
+            <key>NSPortName</key>
+            <string>Konverter</string>
+            <key>NSSendFileTypes</key>
+            <array>
+                <string>public.item</string>
+            </array>
+            <key>NSRequiredContext</key>
+            <dict/>
+        </dict>
+    </array>
+</dict>
+</plist>
+PLIST
+
+chmod +x scripts/make-icon.sh
+./scripts/make-icon.sh
+
+if [ -n "$IDENT" ]; then
+    security unlock-keychain "$HOME/Library/Keychains/login.keychain-db" 2>/dev/null || true
+    codesign --force --options runtime --timestamp --sign "$IDENT" "$APP"
+    echo "Built $APP $VERSION (signed with Developer ID '$IDENT')"
+else
+    codesign --force --sign - "$APP"
+    echo "Built $APP $VERSION (ad-hoc signed; not distributable)"
+fi