docs(hardware): clarify provisional cluster note in naming spec

notes/dev/specs/2026-06-24-hardware-naming-scheme.md

@@ -95,7 +95,7 @@ Such hosts carry no `rack:` field and need no `cluster:`.
 | Current | New | Notes |
 |---------|-----|-------|
 | `mf00` | `srv01` | "TaPPaaS node 1" → `cluster: tappaas` |
-| `mf01` | `srv02` | set `cluster:` per its real assignment |
+| `mf01` | `srv02` | cluster omitted until a real assignment is given |
 | `mf02` | `srv03` | |
 | `mf03` | `srv04` | |
 | `mf04` | `srv05` | |