A public, read-only web view of the directory (#215)

The directory renders its own pages from the store: the most subscribed, categories, A to Z,
search, and a page per feed with its address and a Copy button. No token, nothing that writes; /v1
keeps its token check. The publisher's HTML is shown as text, item links only when http(s), with
a strict Content-Security-Policy; covers load from their publishers with no referrer.

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

docs/directory.md

@@ -36,6 +36,17 @@ server's snapshot takes its feeds and counts out until it next shares; to keep a
 revoke its token. An admin's own subscriptions open as their feeds, not as Directory pages, so
 removing one of those is done by marking it private, or from another admin's account.
 
+## In a web browser
+
+Anyone may browse it at its address, no token and no sign-in (#215): the most subscribed, the
+categories, every feed A to Z, a search by name, and a page for each feed with its description,
+its latest items and its address, with a Copy button, to subscribe to in any podcast app or feed
+reader. The pages only read: nothing in them changes the directory. They are rendered by the
+directory itself from what the API serves, with the publisher's HTML shown as text, an item's link
+only when it is http(s), and a Content-Security-Policy that allows the site's own script and
+stylesheet and the covers, which load from their publishers. `/v1` is the API and still needs a
+token for everything.
+
 ## Tokens
 
 Everything but `/healthz` needs a token, sent as `Authorization: Bearer <token>`. Each one has a