[Code scan] NVT TI task generation references an unset pressure #124

Source: Codex global repository scan of deepmodeling/dpti at commit b719828.
Project: DeepModeling Agent Code Scan

Problem
The supported NVT temperature-path branch in ti.make_tasks() never assigns pres, but later passes pres=pres into _gen_lammps_input(). This makes valid ens='nvt', path='t' task generation fail with UnboundLocalError.

Code references

Reproduction
Call ti.make_tasks() with minimal valid NVT/T-path settings. The branch accepts the configuration at lines 143-150, then fails when building the first task because pres was not defined.

Expected result
NVT task generation should either not pass pressure to _gen_lammps_input() or initialize a harmless/default pressure value for the generator.