#2565 setup: the --families probe runs with the engine's library folders, so a ready-made engine can load (#2372)

Descrição

Fixes #2372 for both ready-made engines. It covers the HIP case of #2376 the same way (same folders, same order) and
adds the CUDA case @mocchan0221 found in the thread; it touches the same lines, so only one of the two can merge as
is.

**What it changes.** `install_own_path()` (Qwen3.6) asks the engine which families it runs with `strata --families`,
launched with the inherited environment. A ready-made engine's loader wants its libraries before `main`: hipBLAS
in `engine\rocm\bin` (Windows HIP: two "was not found" dialogs) and cuBLAS from pip's wheels (the CUDA zip, whose
`BUILD.json` has no `lib_dirs`: `cublas64_13.dll ... cannot open shared object file`, exit 127). The probe printed
nothing and setup stopped with "this engine (0.1.44.1) does not run Qwen3.6-35B-A3B yet". `engine_families(eng,
lib_dirs)` now takes the list `engine_step()` already returns for the server's config (`hip_lib_dirs` for the
Windows HIP engine; else `lib_dirs`, `cuda_dirs` or pip's CUDA folders) and puts the folders that exist first on
`PATH` (Windows) or `LD_LIBRARY_PATH` (elsewhere), as the server's `child_env` does.

**What it leaves alone.** With no such folder the probe runs exactly as before (`env=None`). The rest of the
environment is kept. Flash-Next installs do not run this probe. What the engine prints and how setup reads it.

**How it was checked.**
- `tools/test_setup_qwen36.py`: new `FamiliesProbe` (the folders first on PATH with `WIN`, on LD_LIBRARY_PATH
  without; a missing folder skipped; no folders: `env` is None, as before) and `InstallOwnPath` now checks that
  `install_own_path` passes `engine_step`'s list. On `main`: 3 errors and 1 failure. With it: 14 OK.
- `tools/test_setup_choices.py`, `tools/test_setup_amd.py`: OK.
- Python 3.14, Ubuntu (Linux 7.0); no GPU needed. Not run on Windows or with a real ready-made engine; the
  reporter's manual check in the thread (the cu13 folder on PATH, then `--families` prints `qwen4exp qwen35moe`)
  is the case the new PATH entry reproduces.

🤖 Generated with [Claude Code](https://claude.com/claude-code)