fix: Add support for external PostgreSQL and Redis instances

Implements smart detection that allows users to provide external DATABASE_URL
or REDIS_URL. When external services are detected, internal instances are
automatically disabled to save resources. Maintains full backward compatibility
with existing setup

docker/unified/redis-start.sh

@@ -1,5 +1,11 @@
 #!/bin/bash
 # Redis startup wrapper for unified container
+# Smart supervisor: detects external Redis and sleeps instead of starting local instance
+#
+# Behavior:
+# - If REDIS_URL points to external host (not 127.0.0.1/localhost), sleep infinity
+# - Otherwise, start local Redis instance
+#
 # Uses gosu to ensure correct PUID:PGID for file operations
 #
 # Supports:
@@ -15,11 +21,30 @@ if [ -f /etc/environment ]; then
     set +a
 fi
 
+echo "[Redis] Checking for external Redis configuration..."
+
+# Extract host from REDIS_URL
+# Format: redis://host:port or redis://:password@host:port
+if [ -n "$REDIS_URL" ]; then
+    # Extract the host part (between :// or @, and :port or end)
+    REDIS_HOST=$(echo "$REDIS_URL" | sed -n 's|redis://\([^:@]*@\)\?\([^:/]*\).*|\2|p')
+    
+    echo "[Redis] Detected REDIS_URL host: $REDIS_HOST"
+    
+    # Check if host is external (not localhost or 127.0.0.1)
+    if [ "$REDIS_HOST" != "127.0.0.1" ] && [ "$REDIS_HOST" != "localhost" ]; then
+        echo "[Redis] ✅ External Redis detected at $REDIS_HOST"
+        echo "[Redis] Skipping local Redis startup - sleeping to keep supervisord happy"
+        exec sleep infinity
+    fi
+fi
+
+echo "[Redis] Starting local Redis server..."
+
 # Get PUID/PGID (default to redis user's current IDs if not set)
 PUID=${PUID:-$(id -u redis)}
 PGID=${PGID:-$(id -g redis)}
 
-echo "[Redis] Starting Redis server..."
 echo "[Redis] Process will run as UID:GID = $PUID:$PGID"
 
 # =============================================================================