feat(dashboard): mesh topology graph + geographic map + node table

- D3 force-directed topology graph with flowing particle animations
- Leaflet geographic map with CartoDB Dark tiles
- Drag-to-reorganize with visible settling (matches Meshview behavior)
- SNR-based edge coloring: excellent/good/fair/marginal/poor
- Node detail panel with neighbor list and external map links
- Sortable/filterable node table
- Region-colored nodes, infrastructure vs client distinction
- Click-to-select synced across graph, map, table, and detail panel

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

dashboard-frontend/src/lib/api.ts

@@ -59,6 +59,19 @@ export interface EdgeInfo {
   quality: string
 }
 
+export interface RegionInfo {
+  name: string
+  local_name: string
+  node_count: number
+  infra_count: number
+  infra_online: number
+  online_count: number
+  score: number
+  tier: string
+  center_lat: number
+  center_lon: number
+}
+
 export interface SourceHealth {
   name: string
   type: string
@@ -222,6 +235,6 @@ export async function fetchDucting(): Promise<DuctingStatus> {
   return fetchJson<DuctingStatus>('/api/env/ducting')
 }
 
-export async function fetchRegions(): Promise<unknown[]> {
-  return fetchJson<unknown[]>('/api/regions')
+export async function fetchRegions(): Promise<RegionInfo[]> {
+  return fetchJson<RegionInfo[]>('/api/regions')
 }