Added litestar API endpoints

[NirrWorks]

Summary

Adds an initial Litestar API inside the osmsg/api package.

This includes two active endpoints for now:

• GET /health
• GET /api/v1/users

The API uses asyncpg to query PostgreSQL and reads the database connection from the DATABASE_URL environment variable.

Changes

• Added osmsg/api/ package with Litestar app, DB pool setup, and users query.
• Added /health endpoint for API health checks.
• Added /api/v1/users endpoint to return ranked user statistics from the current osmsg PostgreSQL tables.
• Kept future stats endpoints commented out for now.
• Added Procfile for deployment.
• Added API dependencies: litestar[standard], asyncpg, and uv.
• Added route tests for the active API endpoints.

Notes

The API currently expects osmsg data to already be exported into PostgreSQL using the current osmsg schema:

• users
• changesets
• changeset_stats
• state

Example local run:

uv run litestar --app osmsg.api.app:app run --host 0.0.0.0 --port 8000

[kshitijrajsharma]

Thanks for the slim PR , beautiful work !
few points ;
add .env example !
add instructions to quickly test the api and the readme , to insert the data and get the api up , usually should be two commands ! expand test cases for real test assertion

[NirrWorks]

Updated. I added:

• .env.example with DATABASE_URL
• README instructions for inserting data into Postgres and starting the API
• two-command quick test flow:
  • uv run osmsg --last day --format psql --psql-dsn "$DATABASE_URL" --name api_last_day
  • uv run --group api litestar --app osmsg.api.app:app run --host 0.0.0.0 --port 8000
• expanded API tests with real TestClient requests and expected JSON response assertions

[NirrWorks]

The API is now hosted on Render and connected to a Neon Postgres database.

Health endpoint:
https://osmsg-1.onrender.com/health

User stats endpoint:
https://osmsg-1.onrender.com/api/v1/user-stats?start=2026-05-02T00:00:00Z&end=2026-05-03T00:00:00Z&limit=10

The database was populated using:
uv run osmsg --last day --summary --format psql --psql-dsn "$DATABASE_URL" --name api_last_day

[kshitijrajsharma]

few minor changes !