feat/dossiers-ngi: dated tip/at bar keeps caller path on edition switch

scripts/dossiers-ngi/caddy-dossiers-ngi.snippet

@@ -19,7 +19,10 @@
 	handle @use {
 		header Set-Cookie "tdpd_edition={re.use.1}; Path=/; Max-Age=31536000; SameSite=Lax"
 		header Cache-Control "private, no-store"
-		redir * / 302
+		# Keep the caller's path (?next=). Never bounce to /. No next → bar page.
+		@next query_regexp next ^(/|/[^/].*)$
+		redir @next {query.next} 302
+		redir * /_cascade/ 302
 	}
 
 	handle /_cascade/* {