feat(openvpn): suggest available OIDC ports and add deployment assets

backend/internal/api/oidc_port_test.go

@@ -0,0 +1,31 @@
+package api
+
+import (
+	"net"
+	"testing"
+)
+
+func TestFindAvailableOIDCPortSkipsReservedAndOccupied(t *testing.T) {
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Skipf("当前环境不允许监听回环端口: %v", err)
+	}
+	defer listener.Close()
+	occupied := listener.Addr().(*net.TCPAddr).Port
+	if occupied < 1024 || occupied > 65533 {
+		t.Skip("系统分配的临时端口无法用于递增测试")
+	}
+	reserved := map[int]bool{occupied + 1: true}
+	if loopbackTCPAvailable(occupied) {
+		t.Fatal("监听中的端口必须视为占用")
+	}
+	available := func(port int) bool { return port != occupied }
+	port, ok := findAvailableOIDCPort(occupied, 1, reserved, available)
+	if !ok || port != occupied+2 {
+		t.Fatalf("递增应跳过已监听及已配置的端口，得到 %d (ok=%t)", port, ok)
+	}
+	port, ok = findAvailableOIDCPort(occupied+1, -1, reserved, available)
+	if !ok || port != occupied-1 {
+		t.Fatalf("递减应跳过已配置及已监听的端口，得到 %d (ok=%t)", port, ok)
+	}
+}