structural refactor and codebase improvements

.env.example

@@ -45,7 +45,9 @@ ALLOW_REGISTRATION=true
 # PORT=3000
 # RATE_LIMIT=60
 # SECURE_COOKIES=true
-# RUST_LOG=presentation=info,tower_http=info,worker=info
+# Handler-level logs come from the `presentation` crate; startup/wiring logs come
+# from `server`. Include both — `server=info` alone silently drops handler logs.
+# RUST_LOG=server=info,presentation=info,tower_http=info,worker=info
 
 # CORS (for SPA development only)
 # CORS_ORIGINS=http://localhost:5173