feat(canvas): raise switch port cap to 64, add port numbers and fibre edge type

Issue #20: bump MAX_BOTTOM_HANDLES 48 -> 64 (covers 48+4 SFP switches) and add
a per-node "Show Port Numbers" toggle that labels each bottom connection point.

Issue #21: add `fibre` as a first-class edge/connection type (bright cyan with a
subtle glow) alongside ethernet/wifi/iot/vlan/virtual/cluster - selectable in the
edge modal, themeable, registered in the React Flow edgeTypes registry, and
round-tripped through YAML import/export.

Backport of homelable-hacs PR #23.

ha-relevant: yes

frontend/src/components/canvas/nodes/BaseNode.tsx

@@ -254,6 +254,20 @@ export function BaseNode({ id, data, selected, icon: typeIcon, width, height }:
         const targetId = `${sourceId}-t`
         return (
           <span key={sourceId}>
+            {data.show_port_numbers && (
+              <span
+                className="absolute font-mono leading-none pointer-events-none select-none"
+                style={{
+                  left: `${leftPct}%`,
+                  bottom: 3,
+                  transform: 'translateX(-50%)',
+                  fontSize: 7,
+                  color: theme.colors.nodeSubtextColor,
+                }}
+              >
+                {idx + 1}
+              </span>
+            )}
             <Handle
               type="source"
               position={Position.Bottom}