OTel Supabase Edge Style

Hosted Supabase Edge Functions do not support the normal native OTel SDK lifecycle today. Use a tiny provider-neutral shim that looks like OTel and can be deleted later if native support lands.

Good reusable API names:

tracer.startActiveSpan("edge.chat", async (span) => { ... });
span.setAttributes({ "tenant.id": tenantId });
span.setStatus({ code: SpanStatusCode.ERROR });
meter.createCounter("llm.tokens.input").add(tokens, attrs);
histogram.record(durationMs, attrs);

Bad reusable API names: