Keycloak theme for the sign-in and sign-out pages (PD-23, PD-26)

Realm petrolyst's login theme, on Keycloak's unstyled base: a slate panel with the logo and its line
beside the form on a soft card; on a phone a slate band above it; light and dark. Satoshi stays out
of Git by its licence (build.sh). The README adds the install steps. Not deployed.

Bands: none (identity theme).

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

keycloak/themes/check-brand.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# The theme's copies of the brand tokens match their home, Petrolyst/design/. Says "not run" in a lone clone of this repository.
+set -u
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+SOURCE="$HERE/../../../design"
+COPIES="$HERE/petrolyst/login/resources/css/brand"
+[ -d "$SOURCE" ] || { echo "not run: no Petrolyst/design/ next to this repository"; exit 0; }
+status=0
+for pair in brand/07_UI_Tokens/petrolyst_tokens.css identity_layer/02_Tokens/product_identity_layer.css; do
+  name="$(basename "$pair")"
+  if cmp -s "$SOURCE/$pair" "$COPIES/$name"; then echo "same    $name"; else echo "DIFFERS $name"; status=1; fi
+done
+exit $status