chore(specs): mark 045 done

[Copxer]

Refs #134

Spec: specs/phase-10-innovation/045-ai-pr-risk-score-and-project-health-explanation.md

Summary

• Marks Spec 045 as done after PR Spec 045 — AI PR risk score + project health explanation #135 was squash-merged.
• Updates Phase 10 trackers to 6/6 complete.
• Syncs the root README Phase 10 status with the spec tracker.

Test plan

• Documentation/bookkeeping-only change; no runtime tests required.
• git diff --cached --check passed before commit.

Self-review notes

• Verified issue Spec 045 — AI PR risk score + project health explanation #134 is closed as completed.
• Bookkeeping uses a PR because main is protected and requires CI.