fix(deploy): keep official templates in the image build context

*.md was excluding templates/docs from Docker context, so COPY and
go:embed could not see prelim_design.md at /app. Un-ignore those trees
and assert the smoke image can cat the official file.

Co-authored-by: Cursor <cursoragent@cursor.com>

.dockerignore

@@ -10,6 +10,8 @@ web/dist
 web/.vite
 bin
 *.md
+!templates/**/*.md
+!configs/**/*.md
 .env
 .env.*
 !.env.example