revert: drop zigbee LQI edge coloring and path highlighting

Split out of this PR — will land separately with reworked zigbee edge
capture/storage. Keeps only the floor plan + generic media upload work.

- Remove getLqiColor + LQI-derived iot edge stroke (edges/index.tsx)
- Remove zigbee path highlight effect (DetailPanel.tsx)
- Remove highlightedPath/setHighlightedPath store state (canvasStore.ts)
- Delete utils/zigbeePathfinding.ts
- Revert associated test scaffolding and package-lock churn

frontend/src/components/canvas/edges/index.tsx

@@ -9,7 +9,7 @@ import {
   type EdgeProps,
   type Edge,
 } from '@xyflow/react'
-import type { EdgeData, EdgeType, NodeData, Waypoint } from '@/types'
+import type { EdgeData, EdgeType, Waypoint } from '@/types'
 import { useThemeStore } from '@/stores/themeStore'
 import { useCanvasStore } from '@/stores/canvasStore'
 import { THEMES } from '@/utils/themes'
@@ -22,13 +22,6 @@ function getVlanColor(vlanId?: number): string {
   return VLAN_COLORS[vlanId % VLAN_COLORS.length]
 }
 
-function getLqiColor(lqi: number): string {
-  if (lqi >= 200) return '#00cc00'
-  if (lqi >= 150) return '#88cc00'
-  if (lqi >= 100) return '#ffaa00'
-  return '#ff3300'
-}
-
 // ── Waypoint drag handle ─────────────────────────────────────────────────────
 
 interface WaypointHandleProps {
@@ -296,8 +289,7 @@ export function HomelableEdge({ id, source, target, sourceHandleId, targetHandle
   const activeTheme = useThemeStore((s) => s.activeTheme)
   const theme = THEMES[activeTheme]
   const sourceType = useStore((s) => s.nodeLookup.get(source)?.type)
-  const targetNode = useStore((s) => s.nodeLookup.get(target))
-  const targetType = targetNode?.type
+  const targetType = useStore((s) => s.nodeLookup.get(target)?.type)
   const isBidirectional = sourceType === 'proxmox' && targetType === 'proxmox'
 
   const waypoints: Waypoint[] = Array.isArray(data?.waypoints) && data.waypoints.length > 0
@@ -323,8 +315,6 @@ export function HomelableEdge({ id, source, target, sourceHandleId, targetHandle
 
   const edgeType: EdgeType = data?.type ?? 'ethernet'
   const edgeColors = theme.colors.edgeColors
-  const highlightedPath = useCanvasStore((s) => s.highlightedPath)
-  const isHighlighted = highlightedPath.includes(id)
 
   const BASE_STYLES: Record<EdgeType, React.CSSProperties> = {
     ethernet: { stroke: edgeColors.ethernet, strokeWidth: 2 },
@@ -338,36 +328,15 @@ export function HomelableEdge({ id, source, target, sourceHandleId, targetHandle
   }
 
   const customColor = data?.custom_color as string | undefined
-
-  // Derive LQI color from the target node's properties for iot edges
-  const lqiColor = (edgeType === 'iot' && targetNode?.data?.properties)
-    ? (() => {
-        const props = (targetNode.data as NodeData).properties ?? []
-        const lqiProp = props.find(
-          (p: { key: string; value: string }) => p.key === 'LQI'
-        )
-        if (lqiProp) {
-          const lqi = parseInt(lqiProp.value, 10)
-          if (!isNaN(lqi)) return getLqiColor(lqi)
-        }
-        return null
-      })()
-    : null
-
-  const pathHighlightColor = '#00d4ff'
-  const strokeColor: string = isHighlighted
-    ? pathHighlightColor
-    : selected
+  const strokeColor: string = selected
     ? theme.colors.edgeSelectedColor
-    : lqiColor
-    ?? customColor
+    : customColor
     ?? (edgeType === 'vlan' ? getVlanColor(data?.vlan_id as number | undefined) : (BASE_STYLES[edgeType].stroke as string ?? edgeColors.ethernet))
 
   const style: React.CSSProperties = {
     ...BASE_STYLES[edgeType],
     ...(edgeType === 'vlan' ? { stroke: getVlanColor(data?.vlan_id as number | undefined) } : {}),
     ...(customColor ? { stroke: customColor } : {}),
-    ...(isHighlighted ? { stroke: pathHighlightColor, strokeWidth: 3, filter: `drop-shadow(0 0 6px ${pathHighlightColor}aa)` } : {}),
     ...(selected ? { stroke: theme.colors.edgeSelectedColor, filter: `drop-shadow(0 0 4px ${theme.colors.edgeSelectedColor}88)` } : {}),
   }