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/modals/__tests__/EdgeModal.test.tsx

@@ -59,6 +59,13 @@ describe('EdgeModal', () => {
     expect(onSubmit.mock.calls[0][0].label).toBeUndefined()
   })
 
+  it('round-trips the fibre type through submit (issue #21)', () => {
+    const onSubmit = vi.fn()
+    render(<EdgeModal open onClose={vi.fn()} onSubmit={onSubmit} initial={{ type: 'fibre' }} />)
+    fireEvent.click(screen.getByRole('button', { name: 'Connect' }))
+    expect(onSubmit.mock.calls[0][0].type).toBe('fibre')
+  })
+
   // ── VLAN ID field ─────────────────────────────────────────────────────────
 
   it('does not show VLAN ID field for ethernet type', () => {