Use the JARL wordmark in the header and as the README banner

The header now shows the login page's wordmark letters (without the rule)
instead of "Jarl" set in Cinzel, so the bundled Cinzel font, its preload
and its licence stanza in the .deb's copyright file are removed: the web
UI needs no web font.

The README opens with the login page's banner, the logo above the
wordmark (artwork/banner.svg). scripts/banner.py builds it from the web
UI's logo.js and brand.js, with light and dark colors, and logo.py runs
it after tracing the logo.

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

CHANGELOG.md

@@ -33,8 +33,7 @@ The first version, to be released as 0.1.0.
   locks root out. Changes are audited under the system user's name via
   `socket`. The systemd unit creates `/run/jarl` (0750).
 - Jarl is released under the MIT License (`LICENSE`), which is installed
-  with the docs and is the Debian package's `copyright` file (with the
-  bundled Cinzel font's OFL).
+  with the docs and is the Debian package's `copyright` file.
 - A Debian package: `make deb` builds `dist/jarl_<version>_<arch>.deb` with
   only `dpkg-deb` (no root), for the host or any other architecture
   (`DEB_ARCH=arm64`). Installing it creates the `jarl` user and directories
@@ -84,8 +83,11 @@ The first version, to be released as 0.1.0.
   appears together with the page.
 - The login page shows an angular, Norse-style "JARL" wordmark drawn as
   SVG paths (`assets/brand.js`) above a rule with a "DNS" node; it follows
-  the light and dark themes. The header's "Jarl" uses Cinzel Bold (SIL OFL),
-  self-hosted as a 13 KB Latin subset.
+  the light and dark themes. The header beside the logo shows the same
+  letters, without the rule, so the UI needs no web font.
+- The README opens with the login page's banner, the logo above the
+  wordmark (`artwork/banner.svg`, built by `scripts/banner.py` from the web
+  UI's own logo and wordmark, with light and dark colors).
 
 - Web UI: wherever an address match list is entered (server, view and zone
   options such as allow-query or allow-transfer, view match lists, ACL