fix: restore complete source code and fix launchers

- Copy complete source code packages from original CodeNomad project
- Add root package.json with npm workspace configuration
- Include electron-app, server, ui, tauri-app, and opencode-config packages
- Fix Launch-Windows.bat and Launch-Dev-Windows.bat to work with correct npm scripts
- Fix Launch-Unix.sh to work with correct npm scripts
- Launchers now correctly call npm run dev:electron which launches Electron app

packages/opencode-config/plugin/hello.js

@@ -0,0 +1,18 @@
+import { tool } from "@opencode-ai/plugin/tool"
+
+export async function HelloPlugin() {
+  return {
+    tool: {
+      hello: tool({
+        description: "Return a friendly greeting",
+        args: {
+          name: tool.schema.string().optional().describe("Name to greet"),
+        },
+        async execute(args) {
+          const target = args.name?.trim() || "CodeNomad"
+          return `Hello, ${target}!`
+        },
+      }),
+    },
+  }
+}