feat: add CLI argument handling and build script

- Added command-line argument parsing to accept input file path instead of hardcoded value
- Added build task to compile standalone executable with deno compile
- Added usage message for incorrect invocation

README.md

@@ -0,0 +1,49 @@
+# dvdsubconvert
+
+A command-line tool built with Deno to extract, convert, and remux DVD subtitles
+from MKV video files into SRT format, then combine them back into a new MKV
+file.
+
+## Prerequisites
+
+Ensure the following tools are installed and available in your PATH:
+
+- [MKVToolNix](https://mkvtoolnix.download/) (provides `mkvmerge` and
+  `mkvextract`)
+- [FFmpeg](https://ffmpeg.org/)
+- [vobsub2srt](https://github.com/ruediger/VobSub2SRT) (for converting VobSub
+  subtitles to SRT)
+
+## Installation
+
+Clone the repository and ensure Deno is installed
+([Deno installation guide](https://deno.land/manual/getting_started/installation)).
+
+## Usage
+
+Run the tool with a single MKV file as input:
+
+```bash
+deno run --allow-run --allow-write --allow-read src/main.ts input.mkv
+```
+
+The tool will:
+
+1. Analyze the MKV file for subtitle tracks.
+2. Extract supported subtitle languages.
+3. Convert VobSub subtitles to SRT format.
+4. Remux the SRT subtitles into a new MKV file named `subit.mkv`.
+
+Supported languages (ISO 639-1 codes):
+
+- English (en)
+- Finnish (fi)
+
+## Output
+
+- `subit.mkv`: The resulting MKV file with converted SRT subtitles.
+- Temporary files (`.srt`, `.idx`, `.sub`) are cleaned up automatically.
+
+## License
+
+[Include license info from LICENSE file]