refactor(openflare): migrate console APIs to v1 and centralize routing

Move OpenFlare management endpoints to /api/v1/custom/openflare with
Wavelet response envelopes and Abort* error handling. Keep agent, relay,
and flared protocol routes on /api/* with the legacy compat format.

- Add apiutil helpers and Swagger annotations for console handlers
- Register all OpenFlare routes in internal/router/openflare (not apps)
- Switch frontend services to OpenFlareBaseService and v1 paths
- Remove dead auth/compat code and legacy-base.service.ts
- Update integration tests and changelog

Wavelet/internal/apps/openflare/apiutil/routes.go

@@ -0,0 +1,19 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package apiutil
+
+import (
+	"strings"
+
+	"github.com/gin-gonic/gin"
+)
+
+// RegisterCollection registers a collection endpoint on both "" and "/" so requests
+// work with or without a trailing slash.
+func RegisterCollection(route *gin.RouterGroup, method string, handlers ...gin.HandlerFunc) {
+	route.Handle(method, "/", handlers...)
+	if !strings.HasSuffix(route.BasePath(), "/") {
+		route.Handle(method, "", handlers...)
+	}
+}