directory.toml's fetch_internal lets the refresher reach listed addresses (#329)

3bfd8f8 gave the refresher the guard with no exceptions, which broke
the browser suite: its directory refreshes fixture feeds on 127.0.0.1,
and five Directory tests waited on listings that never filled. The
cargo tests passed because none of them fetches over HTTP.

directory.toml takes fetch_internal as config.toml does, empty by
default; the suite's lists 127.0.0.1. Production's has none.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/directory.md

@@ -83,6 +83,9 @@ bind = "0.0.0.0:8100"
 metrics_bind = "0.0.0.0:9188"
 # Apple Podcasts' top charts for this country, weekly (see below). Empty, or left out: none.
 apple_country = "ca"
+# Internal addresses and networks feeds may be fetched from, as ["10.0.0.5", "192.168.1.0/24"].
+# Empty, or left out: nothing off the public internet is fetched (#329).
+fetch_internal = []
 # The environment variable holding the database URL: postgres://... or sqlite://...
 database_url_env = "DIRECTORY_DATABASE_URL"