♻️ sync owner migration and facade thinning

docs/api/library-async-logger-shutdown.md

@@ -2,8 +2,8 @@
 name: library-async-logger-shutdown
 group: api
 category: facade
-update-time: 20260614
-description: Gracefully stop a LibraryAsyncLogger by delegating to the wrapped async logger's shutdown behavior, including runtime-dependent drain and worker-wait rules.
+update-time: 20260707
+description: Gracefully stop a LibraryAsyncLogger by delegating to the wrapped async logger's shutdown behavior, including drain and worker-wait rules.
 key-word:
     - async
     - library
@@ -39,13 +39,12 @@ Detailed rules explaining key parameters and behaviors
 
 - This method delegates directly to the wrapped async logger's `shutdown(...)` behavior.
 - `clear=false` first waits for idle, then closes the logger.
-- If the active async runtime uses shutdown clearing after idle and backlog still remains, the wrapped logger falls back to `close(clear=true)`.
+- If backlog still remains after `wait_idle()` because failure stopped progress early, the wrapped logger falls back to `close(clear=true)`.
 - `clear=true` immediately closes and abandons pending records, even if the facade never started a drain worker for the wrapped logger.
-- In runtimes where shutdown waits for workers, the method then waits until the worker is no longer running before returning.
-- After a worker-failure short-circuit, native-worker backends can still convert remaining backlog into dropped records, while compatibility backends skip that extra forced-clear step.
-- In the current direct facade coverage, the wrapped logger ends that path with `pending_count() == 0` and one more dropped item on native-worker runtimes, versus a still-nonzero pending count and no extra dropped cleanup on compatibility runtimes.
+- The method then waits until the worker is no longer running before returning.
+- After a worker-failure short-circuit, delegated shutdown converts remaining backlog into dropped records before it returns.
 - Delegated shutdown also does not clear retained worker failure state by itself. If the wrapped logger had already recorded a worker error, later inspection through `to_async_logger()` can still show `has_failed=true` and the same `last_error()` string after shutdown completes.
-- The narrower library facade does not change any of these runtime-dependent shutdown rules; it only keeps the broader inspection helpers out of the direct public surface.
+- The narrower library facade does not change any of these shutdown rules; it only keeps the broader inspection helpers out of the direct public surface.
 - Inspecting the logger later through `to_async_logger()` reveals the same delegated shutdown result rather than a rebuilt or translated lifecycle snapshot.
 
 ### How to Use
@@ -79,8 +78,6 @@ e.g.:
 
 - `clear=true` can therefore be used as the facade-level no-worker cleanup path when queued records were accepted but no `run()` task was ever started.
 
-- In compatibility-style runtimes without background-worker waiting, shutdown still closes the logger but may not perform the extra wait-for-worker phase described for native-worker runtimes.
-
 - Even when delegated shutdown finishes with `is_closed=true`, callers can still observe retained `has_failed()` and `last_error()` on the unwrapped logger if the worker had already failed before shutdown cleanup completed.
 
 - If callers skip `shutdown()` and only inspect flags manually, it is easier to leave the worker lifecycle in an unclear state.
@@ -91,7 +88,7 @@ e.g.:
 
 1. Prefer this API over low-level closure control in normal library shutdown paths.
 
-2. Exact post-close waiting behavior depends on the active async runtime mode.
+2. Delegated shutdown waits for an already-running worker to finish before returning.
 
 3. Choose `clear=true` only when loss of queued records is acceptable.