Update welcome and integrations slide copy for DISC audience.

Refine the welcome subtitle and integrations slide messaging per leadership review feedback.

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

Author: matthewbirtch

i18n/en.json

@@ -318,9 +318,9 @@
   "renderer.components.welcomeScreen.slides.calls.title": "Start secure calls instantly",
   "renderer.components.welcomeScreen.slides.collaborate.subtitle": "Coordinate across teams with persistent mission channels, secure file sharing, and automated workflows.",
   "renderer.components.welcomeScreen.slides.collaborate.title": "Collaborate in real time",
-  "renderer.components.welcomeScreen.slides.integrate.subtitle": "Integrate with the tools and systems powering your operations — ticketing, conferencing, alerting, or custom integrations.",
+  "renderer.components.welcomeScreen.slides.integrate.subtitle": "Centralize data feeds, automate alerts, and integrate custom tooling directly into your operational hub.",
   "renderer.components.welcomeScreen.slides.integrate.title": "Integrate with your systems",
-  "renderer.components.welcomeScreen.slides.welcome.subtitle": "Mattermost is a sovereign collaboration platform, purpose-built for operational environments. Secure by design.",
+  "renderer.components.welcomeScreen.slides.welcome.subtitle": "Mattermost is a sovereign collaboration platform built for operational environments and uncompromising security.",
   "renderer.components.welcomeScreen.slides.welcome.title": "Welcome",
   "renderer.downloadsDropdown.ClearAll": "Clear All",
   "renderer.downloadsDropdown.Downloads": "Downloads",

src/renderer/components/WelcomeScreen/WelcomeScreen.tsx

@@ -45,7 +45,7 @@ function WelcomeScreen({
             subtitle: (
                 <FormattedMessage
                     id='renderer.components.welcomeScreen.slides.welcome.subtitle'
-                    defaultMessage='Mattermost is a sovereign collaboration platform, purpose-built for operational environments. Secure by design.'
+                    defaultMessage='Mattermost is a sovereign collaboration platform built for operational environments and uncompromising security.'
                 />
             ),
             image: (
@@ -100,7 +100,7 @@ function WelcomeScreen({
             subtitle: (
                 <FormattedMessage
                     id='renderer.components.welcomeScreen.slides.integrate.subtitle'
-                    defaultMessage='Integrate with the tools and systems powering your operations — ticketing, conferencing, alerting, or custom integrations.'
+                    defaultMessage='Centralize data feeds, automate alerts, and integrate custom tooling directly into your operational hub.'
                 />
             ),
             image: (