docs: finalize and verify Redis-to-Valkey migration and Keycloak hardening

Updated `MASTER_ROADMAP_2026_Q1.md` to reflect completed Redis-to-Valkey migration and Keycloak production configuration. Adjusted property paths in `base-application.yaml` and session logs with corrected environment variable names. Verified end-to-end Docker stability and roadmap alignment.

Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>

config/app/base-application.yaml

@@ -25,12 +25,12 @@ spring:
     baseline-on-migrate: true
     locations: classpath:db/migration
 
-  # --- REDIS KONFIGURATION ---
+  # --- VALKEY KONFIGURATION (Redis-protokollkompatibel, Spring nutzt spring.data.redis.*) ---
   data:
     redis:
-      host: ${SPRING_DATA_REDIS_HOST:localhost}
-      port: ${SPRING_DATA_REDIS_PORT:6379}
-      password: ${SPRING_DATA_REDIS_PASSWORD:redis-password}
+      host: ${SPRING_DATA_VALKEY_HOST:localhost}
+      port: ${SPRING_DATA_VALKEY_PORT:6379}
+      password: ${SPRING_DATA_VALKEY_PASSWORD:}
       connect-timeout: 5s
       timeout: 2s