docs: add CITATION.cff for citable references (no DOI yet — Zenodo needs account)

Author: Harper

CITATION.cff

@@ -0,0 +1,18 @@
+cff-version: 1.2.0
+message: "If you use this software, please cite it as below."
+title: "metal-guard: GPU safety layer for MLX on Apple Silicon"
+abstract: "GPU safety layer for MLX on Apple Silicon — prevents kernel panics from Metal driver bugs, includes a community-curated KNOWN_PANIC_MODELS registry."
+type: software
+authors:
+  - name: "Harper Systems"
+version: "1.1.0"
+license: MIT
+repository-code: "https://github.com/Harperbot/metal-guard"
+url: "https://github.com/Harperbot/metal-guard"
+keywords:
+  - MLX
+  - Apple Silicon
+  - GPU safety
+  - kernel panic
+  - Metal driver
+  - IOGPU