Update RELEASE.md with CSRF_SECRET instructions

Added instructions for the required CSRF_SECRET environment variable for CSRF protection in Kubernetes deployments.

README.md

@@ -1,6 +1,6 @@
 <img src="logoExcaliDash.png" alt="ExcaliDash Logo" width="80" height="88">
 
-# ExcaliDash v0.1.8
+# ExcaliDash
 
 ![License](https://img.shields.io/github/license/zimengxiong/ExcaliDash)
 ![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)

RELEASE.md

@@ -27,3 +27,17 @@ CSRF Protection (8a78b2b)
   - Updated docker-compose configurations with new environment variables
   - E2E test suite improvements and reliability fixes
   - Added Kubernetes deployment note in README
+
+### Kubernetes
+
+  A `CSRF_SECRET` environment variable is now required for CSRF protection. Generate a secure 32+ character random string:
+
+  ```bash
+  openssl rand -base64 32
+
+  Add it to your deployment:
+  - Docker Compose: Add CSRF_SECRET=<your-secret> to the backend service environment
+  - Kubernetes: Add to your ConfigMap/Secret and reference in the backend deployment
+
+  If not set, the backend will refuse to start.
+  ```