refactor: Move Astro to root, use PORT env (default 80), allow all hosts

- Move Astro files from dealplustech-astro/ to project root
- Update Dockerfile: PORT environment variable (default 80)
- Add vite.config.ts with allowedHosts: true
- Matches nixpacks behavior for Easypanel deployment
- No hardcoded ports or domains

node_modules/astro/dist/runtime/server/render/instruction.js

@@ -0,0 +1,13 @@
+const RenderInstructionSymbol = Symbol.for("astro:render");
+function createRenderInstruction(instruction) {
+  return Object.defineProperty(instruction, RenderInstructionSymbol, {
+    value: true
+  });
+}
+function isRenderInstruction(chunk) {
+  return chunk && typeof chunk === "object" && chunk[RenderInstructionSymbol];
+}
+export {
+  createRenderInstruction,
+  isRenderInstruction
+};