Add launch demo and explainable readiness scores

[jacklv-coder]

Summary

• add a reproducible animated terminal demo to both READMEs
• add --explain-score and JSON score component details
• add ready-to-post English and Chinese launch copy
• prepare version 0.7.0 documentation

Verification

• bash -n bin/ipcheck
• bash test/smoke.sh
• shellcheck bin/ipcheck test/smoke.sh
• git diff --check
• English and Chinese docs updated
• demo uses deterministic fixtures and clears credential/routing variables

Review

Independent Codex review found no P1/P2 issues. GPT-5.6 Luna was unavailable in this environment, so the review explicitly fell back to GPT-5.6 Sol.