Feature Request: Support for `pathlib.Path` objects in OTLP Exporter attributes

Is your feature request related to a problem?

Currently, passing a pathlib.Path object as an attribute value to a LogRecord (or Span) causes the OTLP Exporter to fail with an Exception: Invalid type <class 'pathlib.PosixPath'>. While I understand the OTLP spec is strict about primitive types, pathlib.Path is a Python standard library type frequently used in logging context (e.g., model paths, log file locations).

Describe the solution you'd like

It would be helpful if the OpenTelemetry Python SDK could automatically coerce pathlib.Path objects to strings during the OTLP encoding process, or provide a standard hook/configuration to handle common non-primitive types without crashing the exporter.

Describe alternatives you've considered

I am currently using a custom structlog processor to manually stringify all Path objects before they reach the OpenTelemetry logging bridge:

def stringify_non_standard_types(event_dict):
    for key, value in event_dict.items():
        if isinstance(value, Path):
            event_dict[key] = str(value)
    return event_dict

While this works, it requires manual configuration for every project and doesn't cover cases where third-party instrumentations might inject Path objects into the context.

Additional Context

Stack trace:

  File ".../opentelemetry/exporter/otlp/proto/common/_internal/__init__.py", line 100, in _encode_value
    raise Exception(f"Invalid type {type(value)} of value {value}")
Exception: Invalid type <class 'pathlib.PosixPath'> of value /Users/user/models/my-model

Would you like to implement a fix?

Yes

Tip

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Start in opentelemetry/exporter/otlp/proto/common/_internal/init.py at _encode_value, where pathlib.PosixPath currently raises an exception. Trace how OTLP attributes for LogRecord and Span reach this encoder, then verify that Path values are handled as strings without breaking existing primitive encoding or the relevant exporter tests.