Fix /health endpoint: wrap file_server in handle block

try_files is a rewriter that runs before handlers in Caddy's directive
order, rewriting /health to /index.html before handle /health matches.
Wrapping try_files + file_server in a catch-all handle block makes it
mutually exclusive with handle /health.

Caddyfile

@@ -6,6 +6,8 @@
 		respond "ok" 200
 	}
 
-	try_files {path} {path}/index.html {path}/ /index.html
-	file_server
+	handle {
+		try_files {path} {path}/index.html {path}/ /index.html
+		file_server
+	}
 }