feat(scenario): run logs, lint/format tooling, CONTRIBUTING

- add ScenarioRunLogEntity to persist step script output to DB
- stepLogger dual-writes to NestJS logger and DB (fire-and-forget)
- add GET /scenarios/:id/run/:runId returning run, stepRuns and logs
- add POST /scenarios/:id/run/:runId/wait (polls until terminal state)
- 9 new integration tests for the two endpoints (136 total)
- add eslint with typescript-eslint and eslint-config-prettier
- add npm scripts: format, lint, lint:fix
- resolve all lint errors across src and test (no any types)
- add CONTRIBUTING.md covering dev workflow

eslint.config.mjs

@@ -0,0 +1,8 @@
+import tseslint from 'typescript-eslint';
+import eslintConfigPrettier from 'eslint-config-prettier';
+
+export default tseslint.config(
+  { ignores: ['dist/**', 'node_modules/**'] },
+  ...tseslint.configs.recommended,
+  eslintConfigPrettier,
+);