fix(deployment): complete Redis health check fix - update entrypoint script variable syntax

Previous fix (5f7ebd9) only updated health check line but missed entrypoint script.
The entrypoint script was still using $$REDIS_PASSWORD (Docker Compose escaping)
instead of $REDIS_PASSWORD (shell variable syntax).

Changes:
- Line 180: export REDIS_PASSWORD=$(cat ...) - now uses single $
- Line 182: if [ -n "$REDIS_PASSWORD" ] - now uses single $
- Line 190: --requirepass "$REDIS_PASSWORD" - now uses single $

Technical explanation:
The command: block is a multi-line shell script passed to /bin/sh -c.
Within this shell script context, we use normal shell variable syntax with
single $ for variable references. The export statement makes REDIS_PASSWORD
available to both the Redis process and the health check command.

This completes the fix for: "container application-redis-1 is unhealthy"

Related: 5f7ebd9 (health check fix), b1e3a00 (fallback strategy)

docker-compose.production.yml

@@ -177,9 +177,9 @@ services:
     command:
       - |
         # Read password from Docker Secret (as root) and export for health check
-        export REDIS_PASSWORD=$$(cat /run/secrets/redis_password 2>/dev/null || echo '')
+        export REDIS_PASSWORD=$(cat /run/secrets/redis_password 2>/dev/null || echo '')
         # Start Redis with all settings as command line arguments (no config file to avoid conflicts)
-        if [ -n "$$REDIS_PASSWORD" ]; then
+        if [ -n "$REDIS_PASSWORD" ]; then
           exec redis-server \
             --bind 0.0.0.0 \
             --dir /data \
@@ -187,7 +187,7 @@ services:
             --save 300 10 \
             --save 60 10000 \
             --appendonly yes \
-            --requirepass "$$REDIS_PASSWORD"
+            --requirepass "$REDIS_PASSWORD"
         else
           exec redis-server \
             --bind 0.0.0.0 \