feat: add repo-local subminer workflow plugin

plugins/subminer-workflow/.codex-plugin/plugin.json

@@ -0,0 +1,30 @@
+{
+  "name": "subminer-workflow",
+  "version": "0.1.0",
+  "description": "Repo-local SubMiner agent workflow plugin for backlog-first orchestration and change verification.",
+  "author": {
+    "name": "Kyle Yasuda",
+    "email": "suda@sudacode.com",
+    "url": "https://github.com/sudacode"
+  },
+  "homepage": "https://github.com/sudacode/SubMiner/tree/main/plugins/subminer-workflow",
+  "repository": "https://github.com/sudacode/SubMiner",
+  "license": "GPL-3.0-or-later",
+  "keywords": ["subminer", "workflow", "backlog", "verification", "skills"],
+  "skills": "./skills/",
+  "interface": {
+    "displayName": "SubMiner Workflow",
+    "shortDescription": "Backlog-first SubMiner orchestration and verification.",
+    "longDescription": "Canonical repo-local plugin for SubMiner agent workflow packaging. Owns the scrum-master and change-verification skills plus helper scripts used to plan, verify, and validate changes reproducibly inside this repo.",
+    "developerName": "Kyle Yasuda",
+    "category": "Productivity",
+    "capabilities": ["Interactive", "Write"],
+    "websiteURL": "https://github.com/sudacode/SubMiner",
+    "defaultPrompt": [
+      "Use SubMiner workflow to plan and ship a feature.",
+      "Verify a SubMiner change with the plugin-owned verifier.",
+      "Run backlog-first intake for this SubMiner task."
+    ],
+    "brandColor": "#2F6B4F"
+  }
+}