Align plugin manifests and marketplaces with current docs

plugins/.codex-plugin/plugin.json

@@ -2,10 +2,26 @@
   "name": "semantica-codex",
   "description": "Semantica plugin for Codex: knowledge graph commands, export capabilities, and reasoning workflows.",
   "version": "0.1.0",
-  "author": {"name": "Semantica Contributors"},
+  "author": {
+    "name": "Semantica Contributors"
+  },
   "homepage": "https://github.com/Hawksight-AI/semantica",
   "repository": "https://github.com/Hawksight-AI/semantica",
-  "platforms": ["codex"],
-  "keywords": ["semantica", "knowledge graph", "codex", "visualization", "reasoning", "extraction", "mcp"],
-  "license": "MIT"
+  "license": "MIT",
+  "keywords": [
+    "semantica",
+    "knowledge graph",
+    "codex",
+    "visualization",
+    "reasoning",
+    "extraction",
+    "mcp"
+  ],
+  "skills": "./skills",
+  "interface": {
+    "displayName": "Semantica Codex Plugin",
+    "shortDescription": "Knowledge graph skills for Semantica workflows",
+    "category": "Productivity",
+    "developerName": "Semantica Contributors"
+  }
 }