rename: replace all user-facing 'Atlas' references with 'Vibn'

Updated UI text in: project-shell (tab label), AtlasChat (sender name),
FreshIdeaMain, TypeSelector, MigrateSetup, ChatImportSetup, FreshIdeaSetup,
CodeImportSetup, prd/page, build/page, projects/page, deployment/page,
activity/page, layout (page title/description), atlas-chat API route.
Code identifiers (AtlasChat component name, file names) unchanged.

Made-with: Cursor

app/[workspace]/activity/page.tsx

@@ -32,7 +32,7 @@ function typeColor(t: string) {
 
 const FILTERS = [
   { id: "all",    label: "All" },
-  { id: "atlas",  label: "Atlas" },
+  { id: "atlas",  label: "Vibn" },
   { id: "build",  label: "Builds" },
   { id: "deploy", label: "Deploys" },
   { id: "user",   label: "You" },