fix(config): install opencode plugin workspace deps (#360)

Fixes #359

## Summary
- include `packages/opencode-config` in the root npm workspaces
- refresh the root lockfile so fresh installs include
`@opencode-ai/plugin@1.14.19`

## Why
The CodeNomad OpenCode plugin imports `@opencode-ai/plugin/tool`, but
the plugin config package was not part of the root workspace install.
Fresh clones could skip that dependency and fail plugin startup.

## Validation
- npm install --ignore-scripts --workspaces --include-workspace-root
- npm ls @opencode-ai/plugin --workspace @codenomad/opencode-config
- node --input-type=module -e "const mod = await
import('@opencode-ai/plugin/tool'); if (typeof mod.tool !== 'function')
process.exit(1); console.log('ok')"
- npm run prepare-config --workspace @neuralnomads/codenomad

package.json

@@ -9,7 +9,8 @@
       "packages/server",
       "packages/ui",
       "packages/electron-app",
-      "packages/tauri-app"
+      "packages/tauri-app",
+      "packages/opencode-config"
     ]
   },
   "scripts": {