refactor(core): replace legacy logger with Effect logging (#31310)

packages/core/src/observability.ts

@@ -0,0 +1,21 @@
+export * as Observability from "./observability"
+
+import { NodeFileSystem } from "@effect/platform-node"
+import { Effect, Layer, Logger, References } from "effect"
+import { FetchHttpClient } from "effect/unstable/http"
+import { OtlpSerialization } from "effect/unstable/observability"
+import { Logging } from "./observability/logging"
+import { Otlp } from "./observability/otlp"
+
+export const layer = Layer.unwrap(
+  Effect.gen(function* () {
+    const logs = Logger.layer([...Logging.loggers(), ...Otlp.loggers()], { mergeWithExisting: false }).pipe(
+      Layer.provide(NodeFileSystem.layer),
+      Layer.provide(OtlpSerialization.layerJson),
+      Layer.provide(FetchHttpClient.layer),
+      Layer.orDie,
+      Layer.merge(Layer.succeed(References.MinimumLogLevel, Logging.minimumLogLevel())),
+    )
+    return Layer.merge(logs, yield* Effect.promise(Otlp.tracingLayer))
+  }),
+)