[brand] rebrand to Moreminimore Chat (configurable, phase 1)

Set the default brand to Moreminimore Chat while keeping branding
configurable via the existing InstallationConfig/ENV mechanism.

- installation_config.yml: INSTALLATION_NAME/BRAND_NAME -> Moreminimore Chat,
  BRAND_URL/WIDGET_BRAND_URL -> https://www.moreminimore.com,
  TERMS/PRIVACY -> moreminimore.com, MAILER_SUPPORT_EMAIL -> contact@moreminimore.com;
  drop LOGO_DARK (single PNG logo for light+dark).
- Mailer sender defaults -> 'Moreminimore Chat Team <contact@moreminimore.com>'
  across devise.rb, application_mailer, conversation_reply_mailer,
  mail_presenter, email_address_parseable.
- Replace SVG brand assets with logo.png/logo_thumbnail.png (1000x1000);
  update onboarding, super_admin login/nav, Vue login/signup/saml, survey,
  helpcenter, widget, year-in-review to use the single PNG and Moreminimore Chat
  name; remove dark dual-logo pattern.
- manifest.json name/short_name -> Moreminimore Chat; en.yml integration copy.

Approved by independent five-key pre-commit review deleg_a733cdf4
(passed=true, security_concerns=[], logic_errors=[]). Privacy audit findings=0.

app/javascript/dashboard/components/Code.vue

@@ -22,7 +22,7 @@ const props = defineProps({
   },
   codepenTitle: {
     type: String,
-    default: 'Chatwoot Codepen',
+    default: 'Moreminimore Chat Codepen',
   },
 });