Show the whole IP lookup answer, @meta included, on the home page (closes #201)

The home page's IP lookup card showed only the answer's `data` part, or
only the message of an error answer. It now shows the whole answer,
`@meta` included, as the IP information API card does.

The server already added `@meta` to every JSON answer. A new table test
requests every JSON route and checks `@meta` and its fields. It covers
successes, the errors the handlers write, the router's 404 and 405, and
the 500 and 504 the middleware writes.

Model: opus-5-5

TODO.md

@@ -35,6 +35,11 @@ tested.
 
 # Completed Steps
 
+- 2026-10-27: the home page's IP lookup shows the whole JSON answer, with its
+  `@meta`, as the IP information API card does. It used to show only the
+  answer's `data`, or only the message of an error answer. A test checks that
+  every JSON route answers with `@meta`, in its successes and its errors (closes
+  #201)
 - 2026-10-27: every value in a JSON answer that has a unit is a number, with the
   unit at the end of its field name. `@meta.execution_time` is now
   `execution_time_ms`. The stats' `uptime`, `connection_duration` and