fix(keycloak): replace deprecated KC_PROXY with KC_PROXY_HEADERS

KC_PROXY=edge was deprecated and removed in Keycloak 26.x, causing
"Non-secure context detected" warnings and broken cookie handling
behind reverse proxy. Replace with KC_PROXY_HEADERS=xforwarded and
KC_HTTP_ENABLED=true.

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Kirill Ilin <stitch14@yandex.ru>

packages/system/keycloak/templates/sts.yaml

@@ -82,8 +82,10 @@ spec:
               value: "ispn"
             - name: KC_CACHE_STACK
               value: "kubernetes"
-            - name: KC_PROXY
-              value: "edge"
+            - name: KC_PROXY_HEADERS
+              value: "xforwarded"
+            - name: KC_HTTP_ENABLED
+              value: "true"
             - name: KEYCLOAK_ADMIN
               value: admin
             - name: KEYCLOAK_ADMIN_PASSWORD