[transfix]

Fixes a hang in the material Ariadne port from #147.

The bug

• The port runs both stories as async functions under pycvc_gl.ariadne.Host's default per-action cap (ariadne.limits.action_max_time, 30 s).
• The scenario story takes 25-30 s on the Windows test box, so on a busy machine the cap stops its program.
• Its status then never becomes done, and --headless / --offscreen wait forever.
• Locally, test_material_runs_both_stories hung twice in full runs; both times the run was killed at the 1500 s timeout.
• Reproduced on main (749a4fd): with the cap forced to 3 s, both runs are stopped (time_limit_exceeded) and the port never returns.

The fix

• ariadne/material.py:
  • The runs have no time or step cap (RUN_LIMITS, 0 = none). Each story already ends on its own step budget: 4000 steps for the scenario, --swarm-steps for the swarm.
  • Each startup run reports back through run_program's done callback. A run that does not finish sets its status to failed: <why>, so the window's spinner stops.
  • With --headless or --offscreen, the port then ends with exit code 1 and prints the reason.
• tests/test_ariadne_ports.py: test_material_returns_when_a_run_is_stopped replaces both stories with slow stand-ins and sets a 0.2 s cap. It checks that the port returns 1 within 30 s and names both runs. On the old code this test would hang.
• ariadne/README.md: a line on the uncapped runs and the exit code.

Tests

• Locally (Windows, Python 3.11, pycvc/pycvc_gl built from pycvc_gl.ariadne: a Python host for Ariadne documents transfix/libcvc#985), GRL_SNAM_ARIADNE_GL=1 pytest tests/test_ariadne_ports.py tests/test_cli.py: 15 passed in 25 s.
• ruff and black are clean.
• In this repo's CI the port tests still skip until a pycvc release carries pycvc_gl.ariadne: a Python host for Ariadne documents transfix/libcvc#985.