fix: ensure scores are strictly between 0 and 1

feat: run multiple tasks for submission grading

fix: run environment in-process by default

fix: default ENV_BASE_URL to localhost:8000 for Docker container

fix: add local in-process environment fallback

fix: default ENV_BASE_URL to HuggingFace space

fix: load env vars at module level for API proxy

refactor: update environment variable handling and improve logging function signatures

refactor: update type hints to use built-in generic types and improve logging function signatures

Refactor inference and logging mechanisms; remove log_utils.py

refactor: update environment variables and reward validation range

refactor: remove Serper backend support and related configurations

added support for the serper api