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

components/project-main/FreshIdeaMain.tsx

@@ -273,7 +273,7 @@ export function FreshIdeaMain({ projectId, projectName }: FreshIdeaMainProps) {
                     <div style={{ fontSize: "0.65rem", color: "#a09a90", marginTop: 2, lineHeight: 1.3 }}>
                       {phase === null
                         ? "Generated when PRD is finalized"
-                        : "Complete this phase in Atlas"
+                        : "Complete this phase in Vibn"
                       }
                     </div>
                   )}