chore: add docker compose files and solution folder

- docker/environments/docker-compose.yml: base Api + Worker service definitions
- docker/environments/docker-compose.Development.yml: local PostgreSQL + Seq + port mappings
- Solution folder /docker/ in .slnx for IDE access

Ref: IT-628

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docker/environments/docker-compose.yml

@@ -0,0 +1,22 @@
+services:
+  api:
+    build:
+      context: ../..
+      dockerfile: HrynCo.NotificationService.Api/Dockerfile
+    environment:
+      - ASPNETCORE_ENVIRONMENT=Production
+      - App__ConnectionString=${CONNECTION_STRING}
+    ports:
+      - "8080:8080"
+    depends_on:
+      - db
+
+  worker:
+    build:
+      context: ../..
+      dockerfile: HrynCo.NotificationService.Worker/Dockerfile
+    environment:
+      - DOTNET_ENVIRONMENT=Production
+      - App__ConnectionString=${CONNECTION_STRING}
+    depends_on:
+      - db