📝 clarify built async text target behavior

docs/api/build-application-text-async-logger.md

@@ -43,6 +43,7 @@ Detailed rules explaining key parameters and behaviors
 - A sync queue configured on `LoggerConfig.queue` is therefore ignored by this builder instead of being preserved under the returned async logger.
 - Because the result is only the `ApplicationTextAsyncLogger` alias over `AsyncLogger[@bitlogger.FormattedConsoleSink]`, this builder returns the same underlying async logger value as `build_async_text_logger(...)` and does not hide any async helpers or introduce a wrapper layer.
 - The returned alias also keeps inherited async logger target behavior such as `with_target(...)`, `child(...)`, and per-call `target=` overrides on `log(...)`.
+- In particular, `log(..., target=...)` can override the target for one call, while severity helpers such as `debug(...)`, `info(...)`, `warn(...)`, and `error(...)` continue using the stored logger target unless code derives another logger first with `with_target(...)` or `child(...)`.
 - The returned logger keeps the full async lifecycle and state helper surface directly, including helpers such as `run()`, `shutdown()`, `pending_count()`, `dropped_count()`, `state()`, `wait_idle()`, `has_failed()`, and `last_error()`.
 - It also keeps the same close, queue, and failure-state semantics as the underlying `AsyncLogger[@bitlogger.FormattedConsoleSink]`.
 - In the current direct text-builder coverage, this alias matches `build_async_text_logger(config)` through serialized state snapshots, formatter behavior, queue counters, lifecycle flags, and later failure fields after worker execution.
@@ -70,6 +71,18 @@ In this example, the async logger is built for text-console output specifically.
 
 And the returned value keeps the ordinary async logger target semantics because this facade does not wrap or narrow the underlying `AsyncLogger[@bitlogger.FormattedConsoleSink]`.
 
+#### When Need A Per-call Target Override After App Text Construction
+
+When typed app async text config should still build a logger that supports a one-call target override:
+```moonbit
+let logger = build_application_text_async_logger(config)
+logger.log(@bitlogger.Level::Error, "boom", target="app.text.audit")
+```
+
+In this example, the emitted record uses `app.text.audit` for that call.
+
+And later `debug(...)`, `info(...)`, `warn(...)`, or `error(...)` calls still use the logger's stored target unless code derives another logger first with `with_target(...)` or `child(...)`.
+
 #### When Need Async State Helpers Immediately After Text App Construction
 
 When application code should keep the ordinary async helper surface directly on the text-console variant:

docs/api/build-async-text-logger.md

@@ -39,6 +39,7 @@ Detailed rules explaining key parameters and behaviors
 - Unlike `build_async_logger(...)`, this helper does not run the full synchronous `build_logger(config.logger)` path first.
 - That means it uses `config.logger.sink.text_formatter`, `min_level`, `target`, and `timestamp` directly, but it does not apply `LoggerConfig.queue` or preserve other sync runtime sink controls.
 - This builder returns the underlying `AsyncLogger[@bitlogger.FormattedConsoleSink]` value directly. `build_application_text_async_logger(...)` only re-exports that same result under the `ApplicationTextAsyncLogger` alias, while `build_library_async_text_logger(...)` wraps the same result in `LibraryAsyncLogger[@bitlogger.FormattedConsoleSink]`.
+- The returned async logger also keeps ordinary target rules unchanged: `log(..., target=...)` can override the target for one call, while severity helpers such as `debug(...)`, `info(...)`, `warn(...)`, and `error(...)` continue to use the stored logger target unless a derived logger was created first with `with_target(...)` or `child(...)`.
 - In the current direct text-builder coverage, the returned logger exposes the expected serialized async state snapshot, formatter behavior, queue counters, lifecycle flags, and later failure fields after worker execution.
 - The async `flush_policy` still comes from `config.async_config`, but this text-specific builder does not supply the explicit `flush=fn(sink) { sink.flush() }` callback used by `build_async_logger(...)`.
 - In practice, `Batch` and `Shutdown` therefore only trigger the default no-op async flush callback on this path, while each record write still follows whatever immediate behavior `FormattedConsoleSink` already has on its own.
@@ -63,6 +64,18 @@ let logger = build_async_text_logger(
 
 In this example, the async logger is built around a text console sink rather than the generic runtime sink enum.
 
+#### When Need A Per-call Target Override After Built Async Text Construction
+
+When typed async text config should still build a logger that supports a one-call target override:
+```moonbit
+let logger = build_async_text_logger(config)
+logger.log(@bitlogger.Level::Error, "boom", target="async.text.audit")
+```
+
+In this example, the emitted record uses `async.text.audit` for that call.
+
+And later `debug(...)`, `info(...)`, `warn(...)`, or `error(...)` calls still use the logger's stored target unless code derives another logger first with `with_target(...)` or `child(...)`.
+
 ### Error Case
 
 e.g.:

docs/api/build-library-async-text-logger.md

@@ -44,6 +44,7 @@ Detailed rules explaining key parameters and behaviors
 - In the current direct text-builder coverage, unwrapping this facade yields the same async state snapshot, formatter behavior, queue counters, lifecycle flags, and later failure fields as calling `build_async_text_logger(config)` directly.
 - The configured `flush_policy` is still carried by that underlying async logger, but this text-specific builder path does not provide the explicit sink flush callback used by `build_library_async_logger(...)` through `build_async_logger(...)`.
 - As a result, `Batch` and `Shutdown` only invoke the default no-op async flush callback on this text-console path unless downstream code unwraps and adds different behavior elsewhere.
+- The facade still preserves the underlying async target rules on its exposed write methods: `log(..., target=...)` can override the target for one call, while `info(...)`, `warn(...)`, and `error(...)` continue using the stored logger target unless the facade first derived another logger with `with_target(...)` or `child(...)`.
 - Async state helpers such as `pending_count()`, `dropped_count()`, `state()`, `wait_idle()`, and failure-status inspection remain on the underlying `AsyncLogger[@bitlogger.FormattedConsoleSink]`, not on the returned facade itself.
 - `to_async_logger()` can recover the underlying full async logger if needed.
 - Use this builder when the boundary should preserve the concrete text-console sink type while still hiding broader async inspection and helper APIs from downstream callers.
@@ -77,6 +78,18 @@ ignore(full.pending_count())
 
 In this example, the facade is unwrapped before using async state helpers.
 
+#### When Need A Per-call Target Override Through The Library Async Text Builder Facade
+
+When typed library async text config should still build a facade that allows a one-call target override without unwrapping first:
+```moonbit
+let logger = build_library_async_text_logger(config)
+logger.log(@bitlogger.Level::Error, "boom", target="lib.text.audit")
+```
+
+In this example, the emitted record uses `lib.text.audit` for that call.
+
+And later `info(...)`, `warn(...)`, or `error(...)` calls still use the facade's stored target unless code derives another facade first with `with_target(...)` or `child(...)`.
+
 ### Error Case
 
 e.g.: