fix: firstboot reprovision path now runs hostname, user, and registration

Previously the reprovision path exited early after re-mounting LVs,
skipping hostname setup, admin user creation, metadata, and bastion
registration. Now both paths fall through to the common post-setup code.

Tested on Mac Studio (worker1-k8s0) — reprovision + self-registration
confirmed working via curl | bash pipe.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

bastion/src/bastion/src/templates/asahi-firstboot.sh.ts

@@ -141,10 +141,7 @@ ${roleFstabLines.map(l => `        ${l}`).join('\n')}
     }
 
     echo "Existing LVM volumes re-mounted."
-    touch "$MARKER"
+else
-    exit 0
-fi
-
 # ── Fresh install: create LVM ────────────────────────────────────
 echo "Creating LVM on $DATA_PART..."
 
@@ -223,6 +220,8 @@ ${roleFstabLines.join('\n')}
 echo "LVM setup complete."
 lvs labvg
 
+fi  # end if/else for reprovision vs fresh install
+
 # ── Set hostname ─────────────────────────────────────────────────
 hostnamectl set-hostname "${hostname}"