feat(api): add endpoint to list community prefixes with pagination

Introduced a new GET endpoint `/v1/communities/{id}/prefixes` to retrieve unique prefixes associated with a community, including pagination support via cursor and limit parameters. Updated OpenAPI documentation to reflect this addition. Implemented backend logic in both PostgreSQL and in-memory storage to handle the new functionality, ensuring proper authorization checks and response formatting.

internal/httpapi/routes_crud.go

@@ -58,6 +58,7 @@ func (s *Server) registerCRUDRoutes(m *http.ServeMux) {
 	m.HandleFunc("GET /communities", s.handleListComm)
 	m.HandleFunc("POST /communities", s.handlePostComm)
 	m.HandleFunc("GET /communities/{id}", s.handleGetComm)
+	m.HandleFunc("GET /communities/{id}/prefixes", s.handleListCommPrefixes)
 	m.HandleFunc("PATCH /communities/{id}", s.handlePatchComm)
 	m.HandleFunc("DELETE /communities/{id}", s.handleDeleteComm)
 
@@ -945,6 +946,39 @@ func (s *Server) handleGetComm(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, commJSON(x))
 }
 
+func (s *Server) handleListCommPrefixes(w http.ResponseWriter, r *http.Request) {
+	a, ok := authFromContext(r.Context())
+	if !ok || !s.requirePerm(w, a, "bgp:directories:read") {
+		return
+	}
+	limit, _ := strconv.Atoi(r.URL.Query().Get("limit"))
+	if limit == 0 {
+		limit = 500
+	}
+	cursor := r.URL.Query().Get("cursor")
+	rows, next, more, err := s.store.ListCommunityPrefixes(a.TenantID, r.PathValue("id"), cursor, limit)
+	if err != nil {
+		writeStoreErr(w, err)
+		return
+	}
+	items := make([]map[string]any, 0, len(rows))
+	prefixes := make([]string, 0, len(rows))
+	for _, pr := range rows {
+		m := map[string]any{"prefix": pr.Prefix}
+		if pr.Source != "" {
+			m["source"] = pr.Source
+		}
+		items = append(items, m)
+		prefixes = append(prefixes, pr.Prefix)
+	}
+	writeJSON(w, http.StatusOK, map[string]any{
+		"items":       items,
+		"prefixes":    prefixes,
+		"next_cursor": strPtrOrNull(next),
+		"has_more":    more,
+	})
+}
+
 func (s *Server) handlePostComm(w http.ResponseWriter, r *http.Request) {
 	a, ok := authFromContext(r.Context())
 	if !ok || !s.requirePerm(w, a, "bgp:directories:write") {