Add optional OpenTelemetry tracing

[loong-solvable]

Summary

• Add an optional OpenTelemetry tracing helper that is disabled by default and no-ops cleanly when OpenTelemetry packages are unavailable.
• Enable OTLP export through SWARMS_OTEL_ENABLED, SWARMS_OTEL_SERVICE_NAME, and the standard OTEL_EXPORTER_OTLP_ENDPOINT environment variable.
• Instrument Agent, AgentRearrange, SequentialWorkflow, ConcurrentWorkflow, SwarmRouter, and MixtureOfAgents run entrypoints with metadata-only spans.
• Add focused tests covering disabled-mode behavior and safe attribute collection.

Privacy

• Span attributes intentionally avoid prompt text, task content, tool arguments, responses, images, and conversation history.
• Captured attributes are limited to component metadata such as component type, name/id, output type, swarm type, and agent count.

Verification

• python3 -m py_compile swarms/telemetry/otel.py swarms/structs/agent.py swarms/structs/sequential_workflow.py swarms/structs/concurrent_workflow.py swarms/structs/swarm_router.py swarms/structs/mixture_of_agents.py swarms/structs/agent_rearrange.py tests/telemetry/test_otel.py
• python3 -m pytest tests/telemetry/test_otel.py -q
• git diff --check

/claim #1199

---

📚 Documentation preview 📚: https://swarms--1612.org.readthedocs.build/en/1612/

[github-actions]

Hello there, thank you for opening an PR ! 🙏🏻 The team was notified and they will get back to you asap.