Add engine 3.0 (BGE-384) work in progress with open-issues list

Correction: v2.0 domain input still carries subreddit names (REPORT.md)

Correction: v2.0 domain input still carries subreddit names (hybrid_engine/README.md)

Correction: v2.0 domain input still carries subreddit names (README.md)

REPORT.md: two-session re-check and new-user results

Add new-user evaluation (results + README section)

README: engine v2.0 is the model to use; older models moved to archive/

Add all trained weights: phase-1 models, v1.1 checkpoints, v1 two-stage engine; model-size section

UniHive RecSys hybrid engine v2.0: ONNX models, code, checkpoints, model card, full report

initial commit