Polish README results and demo clarity

[weitianxin]

Summary

• compress the updated README sections and end choice-token readout with one clear takeaway
• give every JevAny point one blue-circle identity in the inference-efficiency plot
• re-render the efficiency and Playground GIFs at higher native resolution

Validation

• 2 passed, 26 deselected for the affected replay/GIF tests
• modified Python generators compile
• git diff --check
• two independent read-only reviews passed