[Bug]: Extra run configuration properties not ignored when parsing

[jvstme]

Steps to reproduce

Run the snippet:

from dstack._internal.core.models.common import validate_extra_ignore
from dstack._internal.core.models.runs import RunSpec

run_spec = {
    "configuration": {
        "type": "dev-environment",
        "new_prop": 123,
    }
}

print(validate_extra_ignore(RunSpec, run_spec))

Actual behaviour

Traceback (most recent call last):
  File "/dstack/test.py", line 11, in <module>
    print(validate_extra_ignore(RunSpec, run_spec))
  File "/dstack/src/dstack/_internal/core/models/common.py", line 86, in validate_extra_ignore
    return _get_type_adapter(tp).validate_python(obj, extra="ignore")
  File "/dstack/.venv/lib64/python3.10/site-packages/pydantic/type_adapter.py", line 441, in validate_python
    return self.validator.validate_python(
pydantic_core._pydantic_core.ValidationError: 1 validation error for RunSpec
dev-environment.new_prop
  Extra inputs are not permitted [type=extra_forbidden, input_value=123, input_type=int]
    For further information visit https://errors.pydantic.dev/2.13/v/extra_forbidden

Expected behaviour

The extra "new_prop" property is ignored, considering that validate_extra_ignore is used. The snippet exits cleanly.

dstack version

master

Server logs

Additional information

Presumably introduced by #4077.

Implications

• The current client is incompatible with any upcoming server versions that add a new run configuration property.
• Dropping an existing run configuration property breaks the current server, which fails to read older configurations from the database.

[jvstme]

Agent's findings

RunSpec's _merged_profile before-validator (runs.py:591) independently calls RunConfiguration.model_validate(values["configuration"]) to extract profile params for merging. This is a separate validation call that doesn't inherit the caller's extra="ignore" override, so it always defaults to extra="forbid" — rejecting unknown properties before the real (correctly lenient) field validation of configuration ever runs.