feat: collapse mesh.name and mesh.slug into one identifier (v1.21.0)

Pre-launch fix: every visible surface already keyed on slug, so
"name" was a parallel string that only existed to confuse users
on rename ("I renamed but nothing visible changed").

Now slug IS the identifier. claudemesh rename <old> <new> is the
whole rename surface. PATCH /api/cli/meshes/:slug body becomes
{ slug } and the route writes both columns to keep them in sync.
Mesh create derives slug from input.name and stores name = slug.
Pickers drop the (parens). The claudemesh slug verb shipped 30
min ago is removed — merged into rename.

The mesh.name DB column stays for now to avoid touching ~25
reader sites; a follow-up migration drops it.

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

apps/cli/src/commands/delete-mesh.ts

@@ -45,7 +45,7 @@ export async function deleteMesh(slug: string, opts: { yes?: boolean } = {}): Pr
     }
     render.section("select mesh to remove");
     config.meshes.forEach((m, i) => {
-      process.stdout.write(`    ${bold(String(i + 1) + ")")} ${clay(m.slug)} ${dim("(" + m.name + ")")}\n`);
+      process.stdout.write(`    ${bold(String(i + 1) + ")")} ${clay(m.slug)}\n`);
     });
     render.blank();
     const choice = await prompt(`  ${dim("choice:")} `);