docs: text-less Salesforce logo in nav and tagline-based SEO description

Use a mark-only Salesforce cloud logo (no wordmark) in the top nav so it
reads cleanly beside the site title. Align the homepage meta description
with the hero tagline for consistent SEO copy.

Author: clavery

docs/.vitepress/config.mts

@@ -218,7 +218,7 @@ export default defineConfig({
   },
 
   themeConfig: {
-    logo: '/logo.svg',
+    logo: '/logo-mark.svg',
     outline: {
       level: [2, 3],
     },

docs/index.md

@@ -1,5 +1,5 @@
 ---
-description: Developer tools for Salesforce B2C Commerce — CLI, MCP Server, Agent Skills, and SDK. Build and operate B2C Commerce from the terminal or with AI coding agents.
+description: The full power of B2C Commerce, available as a CLI, Agent Skills, and IDE extensions — so you and your coding agent can build, deploy, and operate together.
 layout: b2c-home
 isHome: true