docs(ai): improve onboarding steps (onboarding-audit-agent)

- Added `npx playwright install` to README.md and CONTRIBUTING.md.
- Created docs/agents/task-logs/daily/2026-02-15_03-47-40_onboarding-audit-agent_completed.md.

Co-authored-by: PR0M3TH3AN <[email protected]>

CONTRIBUTING.md

@@ -131,6 +131,14 @@ To set up the project locally:
 
 4. **Run Tests**:
 
+   First, install the required browsers for UI testing:
+
+   ```bash
+   npx playwright install
+   ```
+
+   Then run the tests:
+
    ```bash
    npm run test:unit
    ```

README.md

@@ -174,6 +174,7 @@ To run **bitvid** locally:
    Run tests and linting to ensure everything is working correctly.
 
    ```bash
+   npx playwright install    # Install browsers for smoke/visual tests
    npm run test:unit:shard1  # Run a subset of tests for speed
    npm run test:smoke        # Critical path verification
    npm run format