fix(shim): Map OpenTracing span.kind tag to OTel SpanKind

[Nik-Reddy]

Description

The OpenTracing compatibility shim ignores the span.kind tag when creating spans via TracerShim.start_span(). All spans default to SpanKind.INTERNAL regardless of the OpenTracing span.kind value (client, server, producer, consumer). This breaks interoperability for users migrating from OpenTracing to OpenTelemetry, as span kind is critical for trace visualization and backend processing.

This PR extracts span.kind from the tags dict before span creation, maps it to the corresponding SpanKind enum value (including internal), passes it as the kind= parameter, and removes span.kind from the tags so it does not appear as a duplicate attribute — it is a semantic control tag, not a regular user attribute.

Note: A previous attempt in #4953 was auto-closed by the stale bot (no activity for 28 days). This PR differs in two key ways:

1. It removes span.kind from span attributes after extraction, preventing duplication (the previous PR preserved it as an attribute).
2. The mapping logic is separated into a testable helper function in util.py with dedicated unit tests.

Fixes #2549

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

All existing shim tests plus new test cases pass:

pytest shim/opentelemetry-opentracing-shim/tests/ -v

• test_span_kind_from_tags — 7 sub-tests covering all four OpenTracing kinds + unknown + absent + None
• test_span_kind_tag_removed_from_attributes — verifies span.kind is removed from attributes while other tags are preserved
• test_opentracing_kind_to_otel_kind — 7 sub-tests for the util.py helper (all five valid kinds + unknown + empty)

61 tests passed, 0 failures.

Does This PR Require a Contrib Repo Change?

• No.

Checklist:

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

[MikeGoldsmith]

Looks good - thanks @Nik-Reddy. I've left a couple of suggestions and queries.

Also, please add a changelog entry.

[Nik-Reddy]

Hi @MikeGoldsmith, added the internal kind as suggested, updated the test, and added a CHANGELOG entry. Added \internal\ SpanKind mapping, corresponding test, and CHANGELOG entry.

[MikeGoldsmith]

Thanks for the update @Nik-Reddy. I've left one more suggestion around mutating the tags dic.

[MikeGoldsmith]

del tags["span.kind"] mutates the caller's dict in place. Could you make a copy first to avoid the side effect?

Suggested change

	del tags["span.kind"]
	tags = dict(tags)
	del tags["span.kind"]

[lmolkova]

OpenTracing support is deprecated since March 2026 - https://github.com/open-telemetry/opentelemetry-specification/blob/49ef085d79fd4b9a0ff88135bb7ee6eed74fe8f3/specification/compatibility/opentracing.md

This PR attempts to fix issue from 2022 with no upvotes. It does not seem like fixing this issue would help anyone. I'll leave a comment suggesting to close the issue as not planned.

[Nik-Reddy]

Fair point, makes sense to close this given the deprecation. Thanks for the context.