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/themes.ts

@@ -86,6 +86,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         vlan:     '#00d4ff',
         virtual:  '#8b949e',
         cluster:  '#ff6e00',
+        fibre:    '#22d3ee',
       },
       edgeSelectedColor:  '#00d4ff',
       edgeLabelBackground:'#161b22',
@@ -149,6 +150,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         vlan:     '#22d3ee',
         virtual:  '#6b7280',
         cluster:  '#fb923c',
+        fibre:    '#06b6d4',
       },
       edgeSelectedColor:  '#22d3ee',
       edgeLabelBackground:'#111111',
@@ -212,6 +214,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         vlan:     '#0284c7',
         virtual:  '#9ca3af',
         cluster:  '#ea580c',
+        fibre:    '#0891b2',
       },
       edgeSelectedColor:  '#0284c7',
       edgeLabelBackground:'#ffffff',
@@ -275,6 +278,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         vlan:     '#00ffff',
         virtual:  '#8888cc',
         cluster:  '#ff8800',
+        fibre:    '#00e5ff',
       },
       edgeSelectedColor:  '#00ffff',
       edgeLabelBackground:'#0a0a1a',
@@ -338,6 +342,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         vlan:     '#00cc33',
         virtual:  '#004400',
         cluster:  '#33ff66',
+        fibre:    '#00ffcc',
       },
       edgeSelectedColor:  '#00ff41',
       edgeLabelBackground:'#001100',
@@ -401,6 +406,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         vlan:     '#00d4ff',
         virtual:  '#8b949e',
         cluster:  '#ff6e00',
+        fibre:    '#22d3ee',
       },
       edgeSelectedColor:  '#00d4ff',
       edgeLabelBackground:'#161b22',