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/utils/__tests__/importYaml.test.ts

@@ -89,6 +89,22 @@ describe('parseYamlToCanvas', () => {
     expect(edges[0].targetHandle).toBe('top-t')
   })
 
+  it('imports a fibre link type onto the edge (issue #21)', () => {
+    const yaml = `
+- nodeType: switch
+  label: "SW"
+  links:
+    - label: "SRV"
+      linkType: fibre
+- nodeType: server
+  label: "SRV"
+`
+    const { edges } = parseYamlToCanvas(yaml, empty, emptyEdges)
+    expect(edges).toHaveLength(1)
+    expect(edges[0].type).toBe('fibre')
+    expect(edges[0].data?.type).toBe('fibre')
+  })
+
   it('cluster edges have cluster-right→cluster-left handles', () => {
     const yaml = `
 - nodeType: proxmox