feat: add claude skills for users to use cocoindex to develop (#1205)

* feat: add claude skills for users to use cocoindex to develop

* rename: cocoindex-flows -> cocoindex

* docs: add data type information the skill

* update SKILL.md

Author: georgeh0

.claude-plugin/marketplace.json

@@ -0,0 +1,10 @@
+{
+  "name": "cocoindex",
+  "version": "1.0.0",
+  "description": "Comprehensive toolkit for developing with the CocoIndex library - build data transformation pipelines, create custom functions, and operate flows via CLI or API",
+  "author": "CocoIndex Team",
+  "homepage": "https://github.com/cocoindex-io/cocoindex",
+  "skills": [
+    "cocoindex"
+  ]
+}