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

test/__mocks__/readability.ts

@@ -1,6 +1,6 @@
 export class Readability {
-  constructor(private doc: any) {}
+  constructor(private doc: unknown) {}
   parse() {
-    return { textContent: '' };
+    return { textContent: "" };
   }
 }