📚 Add OpenSpec documentation and metadata entry for spec-driven development tooling

openspec/CHEATSHEET.md

@@ -0,0 +1,20 @@
+# openspec
+
+## Meta
+
+```yaml
+name: openspec
+repo: https://github.com/Fission-AI/OpenSpec
+description: Spec-driven development (SDD) for AI coding assistants.
+```
+
+## Install
+
+```shell
+npm install -g @fission-ai/openspec@latest
+```
+
+Update:
+```shell
+openspec update
+```