docs: media model = git files beside articles (Garage S3 dropped); update README/PLAN/maps

docs/architecture.md

@@ -28,11 +28,11 @@ flowchart LR
   end
 
   subgraph media["Media (Garage S3 on .13)"]
-    S3[(Garage S3<br/>kontra-day bucket)]
+    F[(Images beside articles<br/>in the content repo)]
   end
 
   G -->|"SSH git"| P
-  B -->|"shortcode: media"| S3
+  B -->|"shortcode: media"| F
   B -->|"emits HTML"| CB[Caddy master<br/>.35 :80/:443]
   CB -->|"reverse_proxy :8600"| B