feat(brand): logo placeholder + smoke.sh defaults to wevisto.com

Adds frontend/public/logo.svg as a placeholder (rendered at /build/logo.svg
after Vite build). Email template share_notification.html.twig swaps the
text "WeVisto" header for an <img> referencing /build/logo.svg via
absolute_url, so dropping in the final design swaps one file with no
template change.

bin/smoke.sh HOST now defaults to wevisto.com — legacy host still smoke-
testable via HOST=pictureframe.edholm.me bin/smoke.sh under the dual-
domain coexistence (Option C).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

bin/smoke.sh

@@ -21,8 +21,11 @@
 # the backgrounded SSE subscriber in step 5 sometimes gets killed before it
 # receives data. Reproduces inside this script, not in interactive shell.
 
-HOST="pictureframe.edholm.me"
-SSH_HOST="pictureframe"
+# Defaults to the new wevisto.com host; override with HOST=… to smoke-test
+# the legacy pictureframe.edholm.me alias kept alive under the dual-domain
+# migration (Option C).
+HOST="${HOST:-wevisto.com}"
+SSH_HOST="${SSH_HOST:-pictureframe}"
 TESTBOT_EMAIL="testbot@example.com"
 TESTBOT_PASS="testpass123"
 RED="\033[31m"; GREEN="\033[32m"; RESET="\033[0m"