Remove build artifacts, fix .gitignore

.gitignore

@@ -1,14 +1,13 @@
-# Nexus .gitignore
-
 # Build outputs
-backend/bin/
+**/bin/
-backend/obj/
+**/obj/
-frontend/dist/
+**/dist/
-frontend/node_modules/
+**/node_modules/
 
 # Environment
 .env
 !.env.example
+!.env.template
 
 # IDE
 .idea/
@@ -27,5 +26,9 @@ docker-compose.override.yml
 # Logs
 *.log
 
-# OS temp
+# Temporary
 *.tmp
+*.bak
+
+# pnpm
+pnpm-lock.yaml