Align inference with hackathon validator

Normalize exported score/reward fields to strict (0,1)

Handle inference exceptions and avoid strict-mode crashes

Enforce strict inference: no fallback without proxy vars

Use validator proxy API_BASE_URL+API_KEY in strict inference mode

Implement non-constant deterministic graders and align required inference env vars

fix: rename 'final_score' to 'score' in inference output payload

feat: implement full OpenEnv spec compliance

fix(inference): add rule-based fallback when API keys are absent

fix: eliminate all remaining 0.0/1.0 boundary score values

fix(eval): strictly bound ALL sub-scores to (0, 1)

fix(inference): initialize OpenAI client with API_KEY and default model name

Hackathon submission: Guardian OpenEnv