docs: add WIP construction warning banner (UTF-8 NoBOM)

Author: andrestubbe

README.md

@@ -1,3 +1,6 @@
+> [!WARNING]
+> **🚧 WIP — Active Memory Architecture Optimization & Hardware SIMD Pipeline Extension in Progress.**
+
 # FastImage 0.1.1 [ALPHA-2026-08] — High-Performance Off-Heap Image Processing for Java
 
 [![Status](https://img.shields.io/badge/status-0.1.1-brightgreen.svg)](https://github.com/andrestubbe/FastImage/releases/tag/0.1.1)