Add c4-diagramm

assets/images/c4_diagramm.puml

@@ -0,0 +1,27 @@
+@startuml travel-journey-container
+!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Container.puml
+LAYOUT_LEFT_RIGHT()
+
+LAYOUT_WITH_LEGEND()
+
+title Container diagram — Travel Journey Blog & Map Application
+
+Person(traveler, "Traveler", "Writes blog posts, edits journeys, views maps")
+
+System_Boundary(app_sys, "Travel Journey Platform") {
+
+    Container(web_app, "Frontend SPA", "HTML, CSS, JavaScript", "Static web pages served by browser.\nKey modules: auth, blog, journey-edit, map, markdown.")
+
+    Container(backend_api, "Backend API", "Python (Flask/FastAPI)", "app.py — serves REST endpoints\nfor users, journeys, uploads.\nReads/writes local JSON & file storage.")
+
+    ContainerDb(json_data, "JSON Data Store", "File System", "journeys.json, users.json\n— structured travel & user data.")
+
+    ContainerDb(uploads, "Uploads Storage", "File System", "backend/uploads/\n— user-uploaded images & videos.")
+}
+
+Rel(traveler, web_app, "Views pages, interacts via browser", "HTTPS")
+Rel(web_app, backend_api, "REST API calls (JSON)", "HTTPS")
+Rel(backend_api, json_data, "Reads/Writes", "File I/O")
+Rel(backend_api, uploads, "Stores/Retrieves", "File I/O")
+
+@enduml