Fix Docker build failure, add docker compose file for convenience

[tassa-yoniso-manasi-karoto]

Description

This PR fixes a critical bug that prevents the Docker image from building. The build fails when COPY . . runs without a WORKDIR, causing subsequent RUN commands to fail:

$ sudo docker build -t pythainlp-test .
Password: 
DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
            Install the buildx component to build images with BuildKit:
            https://docs.docker.com/go/buildx/

Sending build context to Docker daemon  148.5MB
Step 1/8 : FROM python:3.12
 ---> b3d245705d9c
Step 2/8 : COPY . .
 ---> aed91cc8d978
Step 3/8 : RUN apt-get update && apt-get install -y --no-install-recommends build-essential libicu-dev  python3-pip python3-venv pkg-config && rm -rf /var/lib/apt/lists/*
 ---> Running in 64978c3d47e5
failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: error during container init: exec: "/bin/sh": stat /bin/sh: no such file or directory

Changes Made

• Added WORKDIR /app directive before COPY . . in Dockerfile
• Added docker-compose.yml for improved development workflow - this simplifies volume mounting, environment variables, and container management with just a single command like docker-compose run pythainlp instead of lengthy docker run commands

The Issue

The repository contains a bin directory. When COPY . . executes without a WORKDIR, it copies all repository contents to the container's root (/). This causes the system's /bin/sh to become inaccessible to subsequent RUN commands, though the exact mechanism is not clear (overwriting?).

Setting WORKDIR before COPY ensures repository contents are isolated in /app, preventing any interference with system directories.

Testing

• Confirmed the original Dockerfile always fails at the RUN step after COPY
• Successfully built the image with WORKDIR added
• Tested PyThaiNLP functionality: docker run -it pythainlp python -c "from pythainlp.tokenize import word_tokenize; print(word_tokenize('สวัสดีครับ'))"
• Tested docker-compose workflow: docker-compose run pythainlp python

Additional Notes

During testing, I discovered the CLI interface (thainlp command) produces no output in Docker containers, though the Python API works correctly. I've reported this separately in issue #1131

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[coveralls]

coverage: 52.88%. remained the same
when pulling c712031 on tassa-yoniso-manasi-karoto:fix-dockerfile
into a069230 on PyThaiNLP:dev.

[bact]

Merged with 2 approvals.
Thank you @tassa-yoniso-manasi-karoto