v0.1.16

Agent attribution fix: AgentEnrichmentProcessor now sets attributes (e.g. agent.id, agent.name, env, llm.cost.usd, span.type) via span.set_attribute() so they are written to the OTel span and exported. Previously it only updated an internal dict, so LLM child spans were exported without agent.id and could be attributed to "unknown-agent-name" when running under an orchestrator (e.g. multi-agent portal). Root spans were correct because they already used set_attribute().