eval() rejects a percent-encoded file:// approval policy URI that read_approval_policies() accepts #5258

Passing an approval policy as a file:// URI works through read_approval_policies() but is rejected by eval(), Task() and inspect eval --approval whenever the path percent-encodes something. Path.as_uri() encodes spaces, so any policy file living under a directory with a space in its name runs into this.

Repro:

from pathlib import Path
from inspect_ai import Task, eval
from inspect_ai.approval import read_approval_policies
from inspect_ai.dataset import Sample

d = Path("/tmp/my policies"); d.mkdir(exist_ok=True)
f = d / "approve.yaml"
f.write_text('approvers:\n  - name: auto\n    tools: "*"\n    decision: approve\n')
uri = f.as_uri()   # file:///tmp/my%20policies/approve.yaml

read_approval_policies(uri)   # fine, 1 policy
eval(Task(dataset=[Sample(input="hello")]), model="mockllm/model", approval=uri)

Actual: the eval call raises ValueError: Invalid approval policy: file:///tmp/my%20policies/approve.yaml. Task(approval=uri) and inspect eval task.py --approval "file:///tmp/my%20policies/approve.yaml" give the same error, and read_approval_policies on that same URI returns the policy.

Expected: all of them take the URI. Move the file to a path with no space and they all do, so it looks specific to the encoding rather than to file:// itself.

One bit of context in case it helps: #4579 listed the eval and task config path next to read_approval_policies, and #5027 closed it, so this may be the half that got missed.

Environment: 58e9b08 (0.3.264.dev9+g58e9b08e7), Python 3.12, Debian slim container.