fix(turn-detector): relax transformers upper bound to allow 5.x

[gdoermann]

Replace the <=4.57.1 cap with targeted excludes for 4.57.2 and 4.57.3, which had a local_files_only=True regression (huggingface/transformers#42369). The bug was fixed in 4.57.4 (huggingface/transformers#42880), so versions 4.57.4+ and 5.x are safe.

The <=4.57.1 cap blocks the entire dependency tree from upgrading to transformers 5.x, which includes a security fix for PVE-2026-85102 (insecure deserialization in Trainer._load_rng_state).

Fixes #5173

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 1 additional finding.

[gdoermann]

-> Vulnerability found in transformers version 4.53.3
Vulnerability ID: 85102
Affected spec: <5.0.0
ADVISORY: Affected versions of the transformers package are
vulnerable to insecure deserialization leading to arbitrary code execution
due to loading an attacker-controlled RNG-state file with an unsafe
torch.load() call.
PVE-2026-85102
For more information about this vulnerability, visit
https://data.safetycli.com/v/85102/97c
To ignore this vulnerability, use PyUp vulnerability id 85102 in safety’s
ignore command-line argument or add the ignore to your safety policy file.

[chenghao-mou]

Seeing a load issue with transformers 5.3.0:

PyTorch was not found. Models won't be available and only tokenizers, configuration and file/data utilities can be used.
Could not find model livekit/turn-detector with revision v0.4.1-intl. Make sure you have downloaded the model before running the agent. Use `python3 your_agent.py download-files` to download the models.
error initializing inference runner
Traceback (most recent call last):
  File "/Users/chenghao/Developer/agents/livekit-agents/livekit/agents/ipc/inference_proc_lazy_main.py", line 69, in initialize
    runner.initialize()
    ~~~~~~~~~~~~~~~~~^^
  File "/Users/chenghao/Developer/agents/livekit-plugins/livekit-plugins-turn-detector/livekit/plugins/turn_detector/base.py", line 149, in initialize
    raise RuntimeError(
    ...<2 lines>...
    ) from None
RuntimeError: livekit-plugins-turn-detector initialization failed. Could not find model livekit/turn-detector with revision v0.4.1-intl and transformers 5.3.0.

[chenghao-mou]

Seeing a load issue with transformers 5.3.0:

PyTorch was not found. Models won't be available and only tokenizers, configuration and file/data utilities can be used.
Could not find model livekit/turn-detector with revision v0.4.1-intl. Make sure you have downloaded the model before running the agent. Use ``python3 your_agent.py download-files`` to download the models.
error initializing inference runner
Traceback (most recent call last):
  File "/Users/chenghao/Developer/agents/livekit-agents/livekit/agents/ipc/inference_proc_lazy_main.py", line 69, in initialize
    runner.initialize()
    ~~~~~~~~~~~~~~~~~^^
  File "/Users/chenghao/Developer/agents/livekit-plugins/livekit-plugins-turn-detector/livekit/plugins/turn_detector/base.py", line 149, in initialize
    raise RuntimeError(
    ...<2 lines>...
    ) from None
RuntimeError: livekit-plugins-turn-detector initialization failed. Could not find model livekit/turn-detector with revision v0.4.1-intl and transformers 5.3.0.

Somehow it requires a re-donwload, then the error goes away.