Split EAPIL skills into selectable plugins

Constraint: Codex installs and removes plugin units, not individual SKILL.md files.\nRejected: Keep every skill in one eapil-skills bundle | Users could not selectively install only the needed skill pack.\nConfidence: high\nScope-risk: moderate\nDirective: Add future skills as separate eapil-* plugins unless they are intentionally bundled.\nTested: python json.tool for marketplace and plugin manifests; validate_plugin.py for all 13 plugins; codex plugin marketplace add . --json; codex plugin list --marketplace eapil-skill-market --available --json; codex plugin add eapil-pdf/eapil-xlsx/eapil-threejs-fundamentals.\nNot-tested: Remote Git marketplace refresh after push.

plugins/codex/plugins/eapil-threejs-lighting/.codex-plugin/plugin.json

@@ -0,0 +1,39 @@
+{
+  "name": "eapil-threejs-lighting",
+  "version": "0.1.0",
+  "description": "EAPIL Three.js Lighting provides Codex guidance for light types, shadow configuration, environment lighting, tone mapping, and visual balance in Three.js scenes.",
+  "author": {
+    "name": "EAPIL",
+    "url": "https://git.playones.com/arechen/EapilSkillMarket"
+  },
+  "homepage": "https://git.playones.com/arechen/EapilSkillMarket",
+  "repository": "https://git.playones.com/arechen/EapilSkillMarket",
+  "license": "Proprietary",
+  "keywords": [
+    "eapil",
+    "threejs-lighting",
+    "codex-skill"
+  ],
+  "skills": "./skills/",
+  "interface": {
+    "displayName": "EAPIL Three.js Lighting",
+    "shortDescription": "Three.js lighting, shadows, and scene illumination guidance.",
+    "longDescription": "EAPIL Three.js Lighting provides Codex guidance for light types, shadow configuration, environment lighting, tone mapping, and visual balance in Three.js scenes.",
+    "developerName": "EAPIL",
+    "category": "Developer Tools",
+    "capabilities": [
+      "Read",
+      "Write"
+    ],
+    "defaultPrompt": [
+      "Use EAPIL Three.js Lighting.",
+      "Improve scene lighting.",
+      "Fix shadows in Three.js."
+    ],
+    "websiteURL": "https://git.playones.com/arechen/EapilSkillMarket",
+    "privacyPolicyURL": "https://git.playones.com/arechen/EapilSkillMarket",
+    "termsOfServiceURL": "https://git.playones.com/arechen/EapilSkillMarket",
+    "brandColor": "#2563EB",
+    "screenshots": []
+  }
+}