chore: ignore db backups and local .idea config files

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -1,12 +1,15 @@
 /target
 database/target
 *.db
+*.db.bak
 .env
 /tmp
 
 # Default ignored files
 .idea/shelf/
 .idea/workspace.xml
+.idea/inspectionProfiles/
+.idea/markdown.xml
 # Datasource local storage ignored files
 .idea/dataSources*
 .idea/dataSources.local.xml