fix(cli): rename syncs local config + picker shows display name

After renaming the mesh display name on the server, the launch
picker still showed the slug ("flexicar-2") because (a) local
config.json was not updated and (b) the picker only printed
mesh.slug. Now: rename writes the new name back into config.json
on success, and the picker prints "name (slug)" when they differ.
Also surfaces a hint that slugs are immutable (today).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/cli/src/commands/launch.ts

@@ -49,7 +49,8 @@ async function pickMesh(meshes: JoinedMesh[]): Promise<JoinedMesh> {
 
   console.log("\n  Select mesh:");
   meshes.forEach((m, i) => {
-    console.log(`    ${i + 1}) ${m.slug}`);
+    const label = m.name && m.name !== m.slug ? `${m.name}  \x1b[2m(${m.slug})\x1b[0m` : m.slug;
+    console.log(`    ${i + 1}) ${label}`);
   });
   console.log("");