Improve MCP tooling and draft exercise publishing

apps/docs/content/docs/mcp.mdx

@@ -1,6 +1,6 @@
 ---
 title: MCP
-description: Connect Claude Code, Codex, Cursor, and other MCP clients to ClassroomIO for draft-based course authoring.
+description: Connect Claude Code, Codex, Cursor, OpenCode, and other MCP clients to ClassroomIO for draft-based course authoring.
 ---
 
 import { Callout } from 'fumadocs-ui/components/callout';
@@ -17,7 +17,7 @@ ClassroomIO API.
 Teacher / Admin
   |
   v
-Claude Code / Codex / Cursor / other MCP client
+Claude Code / Codex / Cursor / OpenCode / other MCP client
   |
   | 1. Reads prompt, PDF, or existing course goal
   | 2. Produces or edits normalized course JSON
@@ -109,6 +109,25 @@ codex mcp add classroomio \
   -- npx -y @classroomio/mcp
 ```
 
+### OpenCode
+
+```json
+{
+  "$schema": "https://opencode.ai/config.json",
+  "mcp": {
+    "classroomio": {
+      "type": "local",
+      "command": ["npx", "-y", "@classroomio/mcp"],
+      "enabled": true,
+      "environment": {
+        "CLASSROOMIO_API_URL": "https://api.classroomio.com",
+        "CLASSROOMIO_API_KEY": "<cio_mcp_key>"
+      }
+    }
+  }
+}
+```
+
 ### Cursor
 
 ```json