docs: added docs

README.md

@@ -2,6 +2,36 @@
 
 Service for managing A/B testing experiments. Drive your tests without breaking user experience!_)
 
+## 🎨 Artifacts
+
+### Runbook
+
+[RUNBOOK.md](./RUNBOOK.md)
+
+### Diagrams
+
+### Testing report
+
+Can be seen in GitLab CI/CD pipeline run
+
+1. Go to the [pipelines page](https://gitlab.prodcontest.com/2026-final-users/backend/itq.dev/-/pipelines)
+2. Click on the latest pipeline run
+![pipeline run](./assets/images/pipeline.png)
+3. Testing report (`Tests` tab)
+![testing report](./assets/images/testing_report.png)
+4. Tests coverage (`Jobs` tab)
+![tests coverage](./assets/images/tests_coverage.png)
+
+Here on screenshot you can see coverage percent (`97%`), for detailed coverage per file go to the `test` job log
+
+![tests coverage per file](./assets/images/tests_coverage_per_file.png)
+
+### Repository map
+
+[MAP.md](./MAP.md)
+
+Yep, artifacts content is written in Russian, but all other docs are in English, this is for judges' convenient experience.
+
 ## 📋 Instructions
 
 ### Dedicated services setup
@@ -52,6 +82,26 @@ docker compose -f compose.prod.yaml up
 
 Thats it, project is already preconfigured for running, so no changes before running this are required.
 
-## Linting and formatting
+## Linting && formatting
 
-Described [here](./src/backend/README.md#)
+Instructions [here](./src/backend/README.md#linting--formatting).
+
+Example run:
+![style](./assets/images/style.png)
+
+## Observability
+
+### Structured logs
+
+![logs](./assets/images/logs.png)
+
+### Health/ready endpoints (`/health`/`/ready`)
+
+![health](./assets/images/health.png)
+![ready](./assets/images/ready.png)
+
+### Metrics (`/metrics`)
+
+![metrics](./assets/images/metrics.png)
+
+System metrics (gc, requests, etc.) and several business metrics (`lotty_decide_requests_total`, `lotty_events_ingested_total"`).