fix: topology — reflect VLAN90 Ceph network and DHCP management separation

10G SFP+ ports on USW-Agg are VLAN90 (10.10.90.x/24, static IPs, Ceph storage).
1G ports on Pro 24 PoE are DHCP management. Update topology to show this:
- USW-Agg sublabel shows VLAN90 · 10.10.90.x (cyan)
- Pro 24 PoE sublabel shows DHCP mgmt (cyan)
- Host sublabels changed from "10G+1G" to "VLAN90" for the 10G Agg connection
- 1G management band label updated to "← 1G DHCP mgmt (Pro 24 PoE) →"
- Add .topo-vlan-tag CSS for cyan VLAN annotation on switch nodes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

static/style.css

@@ -366,6 +366,12 @@ a:hover { text-decoration: underline; text-shadow: var(--glow-amber); }
 
 .topo-badge-unknown { color:var(--text-muted); border-color:var(--border); }
 
+.topo-vlan-tag {
+  color: var(--cyan) !important;
+  opacity: .7;
+  font-size: .54em !important;
+}
+
 /* Switch tier: two switches with horizontal connector */
 .topo-switch-tier {
   display: flex;