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>

Cargo.lock

@@ -1858,6 +1858,7 @@ dependencies = [
 name = "ipx-directory"
 version = "0.1.0-dev"
 dependencies = [
+ "ammonia",
  "anyhow",
  "axum",
  "clap",
@@ -1865,6 +1866,7 @@ dependencies = [
  "opentelemetry",
  "opentelemetry-otlp",
  "opentelemetry_sdk",
+ "percent-encoding",
  "reqwest",
  "sea-orm",
  "serde",