Migrate the /api/regions endpoint to ConnectRPC

main added a dynamically-discovered regions endpoint (region IATA system).
Port it to a RegionsService.GetRegions RPC: new regions.proto (Region /
RegionGroup messages), a handler reusing getAvailableRegions()/getRegionGroups(),
and useRegions/useRegionGroups switched to connect-query against the generated
types. The REST /api/regions route stays for coexistence.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

meshexplorer/proto/meshexplorer/v1/regions.proto

@@ -0,0 +1,31 @@
+syntax = "proto3";
+
+package meshexplorer.v1;
+
+// A dynamically-discovered region (meshcore_regions MV).
+message Region {
+  // Canonical IATA region code, e.g. "SEA".
+  string name = 1;
+  string friendly_name = 2;
+  // Distinct nodes seen in this region (last 30 days).
+  int32 node_count = 3;
+  string last_seen = 4;
+}
+
+// A named set of IATA region codes (region_groups table).
+message RegionGroup {
+  string code = 1;
+  string name = 2;
+  repeated string members = 3;
+}
+
+message GetRegionsRequest {}
+
+message GetRegionsResponse {
+  repeated Region regions = 1;
+  repeated RegionGroup groups = 2;
+}
+
+service RegionsService {
+  rpc GetRegions(GetRegionsRequest) returns (GetRegionsResponse);
+}

meshexplorer/src/hooks/useRegions.ts

@@ -1,37 +1,16 @@
-import { useQuery } from "@tanstack/react-query";
-import { buildApiUrl } from "@/lib/api";
-import type { RegionGroup } from "@/lib/regionGroups";
-
-export interface RegionOption {
-  name: string;
-  friendlyName: string;
-  nodeCount?: number;
-  lastSeen?: string;
-}
-
-interface RegionsResponse {
-  regions: RegionOption[];
-  groups: RegionGroup[];
-}
+import { useQuery } from "@connectrpc/connect-query";
+import { RegionsService } from "@/gen/meshexplorer/v1/regions_pb";
 
 const STALE_TIME = 60 * 60 * 1000; // 1h — the region set is slow-moving / MV-backed
 const GC_TIME = 2 * 60 * 60 * 1000;
 
 // Single shared query (one network request) feeding both useRegions() and useRegionGroups().
 function useRegionsQuery() {
-  return useQuery<RegionsResponse>({
-    queryKey: ["regions"],
-    queryFn: async ({ signal }) => {
-      const response = await fetch(buildApiUrl("/api/regions"), { signal });
-      if (!response.ok) {
-        throw new Error(`Failed to fetch regions: ${response.statusText}`);
-      }
-      return response.json();
-    },
-    staleTime: STALE_TIME,
-    gcTime: GC_TIME,
-    retry: 2,
-  });
+  return useQuery(
+    RegionsService.method.getRegions,
+    {},
+    { staleTime: STALE_TIME, gcTime: GC_TIME, retry: 2 },
+  );
 }
 
 export function useRegions() {

meshexplorer/src/server/connect/regions.ts

@@ -0,0 +1,23 @@
+import type { ServiceImpl } from "@connectrpc/connect";
+import { RegionsService } from "@/gen/meshexplorer/v1/regions_pb";
+import { getAvailableRegions, getRegionGroups } from "@/lib/clickhouse/regions";
+import { num } from "./mappers";
+
+export const regionsServiceImpl: ServiceImpl<typeof RegionsService> = {
+  async getRegions() {
+    const [regions, groups] = await Promise.all([getAvailableRegions(), getRegionGroups()]);
+    return {
+      regions: regions.map((r) => ({
+        name: r.name,
+        friendlyName: r.friendlyName,
+        nodeCount: num(r.nodeCount),
+        lastSeen: r.lastSeen,
+      })),
+      groups: groups.map((g) => ({
+        code: g.code,
+        name: g.name,
+        members: g.members,
+      })),
+    };
+  },
+};

meshexplorer/src/server/connect/routes.ts

@@ -5,12 +5,14 @@ import { NodeService } from "@/gen/meshexplorer/v1/node_pb";
 import { StatsService } from "@/gen/meshexplorer/v1/stats_pb";
 import { ChatService } from "@/gen/meshexplorer/v1/chat_pb";
 import { PacketsService } from "@/gen/meshexplorer/v1/packets_pb";
+import { RegionsService } from "@/gen/meshexplorer/v1/regions_pb";
 import { mapServiceImpl } from "./map";
 import { neighborsServiceImpl } from "./neighbors";
 import { nodeServiceImpl } from "./node";
 import { statsServiceImpl } from "./stats";
 import { chatServiceImpl } from "./chat";
 import { packetsServiceImpl } from "./packets";
+import { regionsServiceImpl } from "./regions";
 
 export default function routes(router: ConnectRouter) {
   router.service(MapService, mapServiceImpl);
@@ -19,4 +21,5 @@ export default function routes(router: ConnectRouter) {
   router.service(StatsService, statsServiceImpl);
   router.service(ChatService, chatServiceImpl);
   router.service(PacketsService, packetsServiceImpl);
+  router.service(RegionsService, regionsServiceImpl);
 }