docs: add SECRETS.md with quick setup for GitHub Actions secrets

Author: oscarj007

docs/SECRETS.md

@@ -0,0 +1,49 @@
+# Adding repository secrets for CI
+
+Use repository secrets to store AWS credentials and cluster name for GitHub Actions. Do NOT commit any keys or kubeconfig files.
+
+Recommended secrets to add (names used by the workflow):
+
+- `AWS_ACCESS_KEY_ID`
+- `AWS_SECRET_ACCESS_KEY`
+- `AWS_REGION`
+- `EKS_CLUSTER_NAME`
+
+Add via GitHub UI:
+
+1. Go to your repository on GitHub.
+2. Settings → Secrets and variables → Actions → New repository secret.
+3. Add each secret with the names above.
+
+Add via GitHub CLI (`gh`) if you have it authenticated:
+
+```bash
+gh secret set AWS_ACCESS_KEY_ID -b "<your-access-key-id>"
+gh secret set AWS_SECRET_ACCESS_KEY -b "<your-secret-access-key>"
+gh secret set AWS_REGION -b "us-east-1"
+gh secret set EKS_CLUSTER_NAME -b "strellerminds-staging"
+```
+
+Local testing (temporary environment variables):
+
+For Bash/WSL:
+```bash
+export AWS_ACCESS_KEY_ID="<your-access-key-id>"
+export AWS_SECRET_ACCESS_KEY="<your-secret-access-key>"
+export AWS_REGION="us-east-1"
+export EKS_CLUSTER_NAME="strellerminds-staging"
+```
+
+For PowerShell (temporary for session):
+```powershell
+$env:AWS_ACCESS_KEY_ID="<your-access-key-id>"
+$env:AWS_SECRET_ACCESS_KEY="<your-secret-access-key>"
+$env:AWS_REGION="us-east-1"
+$env:EKS_CLUSTER_NAME="strellerminds-staging"
+```
+
+After setting secrets or environment variables, the workflow can be triggered manually from Actions (select the `Blue-Green Deploy to EKS` workflow and click "Run workflow") or by pushing to `main`.
+
+PR link (branch pushed by me):
+
+https://github.com/oscarj007/StrellerMinds-SmartContracts/pull/new/add/blue-green-deploy-workflow