docs: tokens in a file, no keyring (U0e)

Deploy recipe loses its D-Bus dance, install.sh its macOS skip, README and
site their macOS caveat; packaging, architecture and testing records follow;
U0e As built filled in (D-63).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp

deploy/wanderbooks-server.service

@@ -26,7 +26,7 @@ Type=simple
 User=wanderbooks
 Group=wanderbooks
 DynamicUser=no
-# The account's own home (the keyring, when one runs; the recorded root).
+# The account's own home (the recorded root).
 StateDirectory=wanderbooks
 Environment=HOME=/var/lib/wanderbooks
 WorkingDirectory=/