✨ add wasm coverage and trace context

docs/api/async-logger-with-trace-context.md

@@ -0,0 +1,21 @@
+---
+name: async-logger-with-trace-context
+group: api
+category: async
+update-time: 20260719
+description: Bind TraceContext fields before records enter an AsyncLogger queue.
+key-word:
+    - async
+    - trace
+    - context
+---
+
+## Async-logger-with-trace-context
+
+```moonbit
+let contextual = logger.with_trace_context(
+  @bitlogger.trace_context("trace-1", "span-1"),
+)
+```
+
+The helper stores the mapped fields on the returned async logger and preserves its queue, lifecycle, target, and threshold state. Context is added before records are enqueued.