Add DB2 auto-initialization support

Implemented auto-initialization for DB2 container using inline bash command:
- Added healthcheck to ensure DB2 database is ready before running init script
- Auto-loads Chinook database with all tables and data on startup
- Uses inline command in docker-compose.yml (no external script files needed)
- Cleaned up environment variables and fixed BLU syntax error

Database initialization verified with 275 artists loaded across 11 tables.

Note: DB2 .NET tests cannot run on macOS ARM64 due to IBM.Data.DB2.Core library limitations,
but the database container itself works correctly and can be tested via docker exec.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: lerocha

docker-compose.yml

@@ -14,29 +14,36 @@ services:
     image: icr.io/db2_community/db2:latest
     platform: linux/amd64
     privileged: true
-    restart: always
     environment:
       LICENSE: accept
       DB2INSTANCE: chinook
       DB2INST1_PASSWORD: chinook
       DBNAME: Chinook
-      BLU=: false
+      BLU: false
       ENABLE_ORACLE_COMPATIBILITY: false
       UPDATEAVAIL: NO
       TO_CREATE_SAMPLEDB: false
       REPODB: false
-      IS_OSXFS: true # identifies the operating system as macOS
-      PERSISTENT_HOME: true # true by default and should only specified as false when running Docker for Windows
+      IS_OSXFS: true
+      PERSISTENT_HOME: false
       HADR_ENABLED: false
-      ETCD_ENDPOINT:
-      ETCD_USERNAME:
-      ETCD_PASSWORD:
     ports:
       - "50000:50000"
     volumes:
-      - ./ChinookDatabase/DataSources/Chinook_Db2.sql:/docker-entrypoint-initdb.d/create_database.sql
-    # Note: DB2 does not auto-run scripts. Manual initialization required:
-    # docker exec chinook-db2-1 su - chinook -c "db2 connect to Chinook && db2 -tf /docker-entrypoint-initdb.d/create_database.sql"
+      - ./ChinookDatabase/DataSources/Chinook_Db2.sql:/scripts/Chinook_Db2.sql
+    healthcheck:
+      test: ["CMD", "su", "-", "chinook", "-c", "db2 connect to Chinook"]
+      interval: 10s
+      timeout: 5s
+      retries: 60
+      start_period: 120s
+    command: >
+      bash -c '
+      /var/db2_setup/lib/setup_db2_instance.sh &
+      until su - chinook -c "db2 connect to Chinook" > /dev/null 2>&1; do sleep 5; done;
+      su - chinook -c "db2 connect to Chinook && db2 -tf /scripts/Chinook_Db2.sql";
+      tail -f /dev/null
+      '
   
   #----------------------------------------------------------------------------
   # MySQL Container