Make reproducibility evidence easier to find

[Dylan-Gallagher]

Adds a passing-main CI badge and a compact, claim-bounded evidence index near the top of the README, plus the exact targeted replay command for the attached-payload result.

Validation:

• documentation-only diff; git diff --check passes
• all added links resolve publicly
• targeted release test passes and reproduces the published fixed-query counts
• simulation-only, sampled-collision, and no-hardware limits remain explicit