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/api/projects/[projectId]/advisor/route.ts

@@ -92,7 +92,7 @@ Operating principles:
     for (const p of phaseRows) {
       lines.push(`- ${p.title}: ${p.summary}`);
     }
-    lines.push(`(PRD not yet finalized — Atlas discovery is in progress)`);
+    lines.push(`(PRD not yet finalized — Vibn discovery is in progress)`);
   } else {
     lines.push(`\n## Product discovery: not yet started`);
   }