fix: align deployment env vars with lunarfront-secrets; add email + encryption env vars

- Fix secret references: all env vars now read from lunarfront-secrets (was referencing 3 non-existent separate secrets)
- Add ENCRYPTION_KEY, RESEND_API_KEY, MAIL_FROM, BUSINESS_NAME, INITIAL_USER_* env vars to backend container
- Add RESEND_API_KEY to manager deployment from manager-secrets

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

manager/deployment.yaml

@@ -81,6 +81,11 @@ spec:
                 secretKeyRef:
                   name: manager-secrets
                   key: cf-zone-id
+            - name: RESEND_API_KEY
+              valueFrom:
+                secretKeyRef:
+                  name: manager-secrets
+                  key: resend-api-key
           resources:
             requests:
               cpu: 50m