build: refresh backend/static/ with rebranded frontend bundle

The committed production bundle in backend/static/ was the pre-rebrand
build from April.  Although the deploy Dockerfile builds the frontend
fresh on every push (so production was always going to get the new
branding once the deploy ran green), local-dev runs of the backend
serve straight out of backend/static/ — which meant `uv run python
start.py` showed the old "SourceBox Sentry" branding even after the
source had been updated.

Ran `npm run build` in frontend/, copied dist/ to backend/static/.
Grepping the fresh bundle for "SourceBox Sentry" returns zero hits.

Includes the doc-page asset images the source already references
(setup-wizard.webp/jpg, system-architecture.webp/jpg, etc.) that
weren't in the older committed bundle.

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

Author: Sbussiso