Implement the event-to-span-event bridge processor

Spec requirement

[Development] A LogRecordProcessor implementation that bridges qualifying LogRecords to span events on the current span. It MUST bridge if and only if: the record has a non-empty EventName, has a valid TraceId and SpanId, the resolved Context's current span IsRecording is true, and the record's TraceId/SpanId match the current span's. When bridged, it MUST add exactly one span event (name = EventName; timestamp = Timestamp if set, else ObservedTimestamp; all Attributes copied), and MUST NOT block the record's normal pipeline (sdk.md:561-600 (permalink)).

Current behavior

This processor has not been implemented.

Suggested fix

Add a new processor implementing the four-condition check and span event mapping described above. Keep it opt-in (not part of the default configured pipeline) since this spec is still marked Development.

Related rows in SPEC_COMPLIANCE_LOGS.md

SDK-41

Start by reading the SDK requirement in sdk.md:561-600 and the SDK-41 entry in SPEC_COMPLIANCE_LOGS.md, then locate the existing LogRecordProcessor entry points in the Ruby repository. Confirm the four bridging conditions, span-event field mapping, opt-in configuration, and that normal record processing remains non-blocking.