Add project scaffolding and documentation

Add .env.example with configuration for database, Redis, security, SMTP, workers, and plugins. Add .gitignore for Python, Node.js, Next.js, Docker volumes, and IDE files. Add MIT License. Update README.md with feature overview, quick start guide, architecture description, plugin system documentation, security details, backup/restore instructions, and developer setup. Add Alembic configuration files and placeholder directories for API, web, worker, and plugin components

plugins/example-plugin/plugin.manifest.json

@@ -0,0 +1,51 @@
+{
+  "id": "example-plugin",
+  "name": "Example Plugin",
+  "version": "1.0.0",
+  "nexadashPluginApi": "1.0",
+  "description": "A minimal example plugin for NexaDash developers.",
+  "author": "NexaDash",
+  "category": "Developer",
+  "permissions": ["network:outbound"],
+  "settingsSchema": {
+    "type": "object",
+    "properties": {
+      "greeting": {
+        "type": "string",
+        "title": "Greeting",
+        "default": "Hello from Example Plugin"
+      }
+    }
+  },
+  "credentialsSchema": {
+    "type": "object",
+    "properties": {
+      "api_key": {
+        "type": "string",
+        "title": "API Key",
+        "format": "password"
+      }
+    }
+  },
+  "widgets": [
+    {
+      "id": "example-card",
+      "name": "Example Card",
+      "description": "Displays a greeting and current timestamp",
+      "defaultWidth": 2,
+      "defaultHeight": 2,
+      "settingsSchema": {
+        "type": "object",
+        "properties": {
+          "showTimestamp": {
+            "type": "boolean",
+            "title": "Show timestamp",
+            "default": true
+          }
+        }
+      }
+    }
+  ],
+  "hasFrontend": true,
+  "apiRoutes": []
+}