Add knowledge graph temporal validity guard

[haki203]

/claim #17

Summary:

• Adds a dependency-free Node.js temporal validity guard for graph nodes, edges, affiliations, recommendation paths, and evidence-version drift.
• Emits suppress/publish decisions, curator actions, deterministic digests, and reviewer artifacts.

Validation:

• npm --prefix knowledge-graph-temporal-validity-guard test
• npm --prefix knowledge-graph-temporal-validity-guard run check
• npm --prefix knowledge-graph-temporal-validity-guard run demo
• npm --prefix knowledge-graph-temporal-validity-guard run video
• ffmpeg decode knowledge-graph-temporal-validity-guard/reports/demo.mp4
• git diff --check
• git diff --cached --check
• secret scan: no matches

Artifacts:

• knowledge-graph-temporal-validity-guard/reports/temporal-validity-packet.json
• knowledge-graph-temporal-validity-guard/reports/temporal-validity-report.md
• knowledge-graph-temporal-validity-guard/reports/summary.svg
• knowledge-graph-temporal-validity-guard/reports/demo.mp4