Update docs to match new dapr[ext] structure

Signed-off-by: Sergio Herrera <627709+seherv@users.noreply.github.com>

Author: seherv

dapr/ext/workflow/AGENTS.md

@@ -122,7 +122,7 @@ Workflow (orchestrator) functions must remain generators (`def` with `yield`). T
 
 **`maximum_thread_pool_workers` covers both paths.** This knob sizes the worker thread pool used for sync-activity bodies and for async-activity gRPC response sends. Mixed workloads with long-running sync activities can starve async response delivery (and vice versa) since they share the pool — size to the sum of peak sync activity concurrency and peak in-flight async response sends.
 
-**Concurrency sizing and load characterization.** See `docs/concurrency.md` for sizing recommendations (`maximum_concurrent_activity_work_items`, `maximum_thread_pool_workers`) and an async-vs-sync decision tree. `tests/durabletask/test_async_dispatch_regression.py` (marked `perf`) guards the core invariant: a batch of async activities overlaps on the event loop instead of serializing through the thread pool.
+**Concurrency sizing and load characterization.** See `docs/concurrency.md` for sizing recommendations (`maximum_concurrent_activity_work_items`, `maximum_thread_pool_workers`) and an async-vs-sync decision tree. `tests/ext/workflow/durabletask/test_async_dispatch_regression.py` (marked `perf`) guards the core invariant: a batch of async activities overlaps on the event loop instead of serializing through the thread pool.
 
 **grpc.aio poller log noise.** The async client can emit benign `BlockingIOError: [Errno 11]` ERROR lines from `grpc.aio`'s `PollerCompletionQueue` under load. It is harmless and retried. `get_grpc_aio_channel` installs an internal `asyncio`-logger filter (`_silence_grpc_aio_poller_noise`) that drops only those records, so the SDK suppresses it automatically with no user action.
 

dapr/ext/workflow/docs/concurrency.md

@@ -1,4 +1,4 @@
-# Concurrency configuration for `dapr-ext-workflow`
+# Concurrency configuration for `dapr.ext.workflow`
 
 Sizing notes for the worker's concurrency knobs.
 

examples/workflow/README.md

@@ -559,3 +559,35 @@ It shows:
 ```sh
 dapr run --app-id workflow-history-propagation -- python3 history_propagation.py
 ```
+
+### Async Activities
+
+This example fans out several `async def` activities, then aggregates their
+results in a sync activity. Each async activity awaits a delay to stand in for
+an I/O call, so the instances run concurrently on the worker's event loop
+instead of taking a thread each.
+
+Fan-out width and payload sizes are set with environment variables:
+`WORKFLOW_FAN_OUT` (default 5), `WORKFLOW_INPUT_BYTES` (default 2048),
+`WORKFLOW_OUTPUT_BYTES` (default 1024), and `WORKFLOW_IO_SECONDS` (default 1.0).
+
+See [concurrency.md](../../dapr/ext/workflow/docs/concurrency.md) for when to
+prefer async over sync activities and how to size the concurrency knobs.
+
+```sh
+dapr run --app-id workflow-async-activities -- python3 async_activities.py
+```
+
+The output should look like this (the async lines can arrive in any order):
+
+```
+Workflow started. Instance ID: 7b3e9c1f...
+[async] payload 0: 2048B in -> 1024B out
+[async] payload 1: 2048B in -> 1024B out
+[async] payload 2: 2048B in -> 1024B out
+[async] payload 3: 2048B in -> 1024B out
+[async] payload 4: 2048B in -> 1024B out
+[sync] 5 results, 5120 bytes
+Workflow completed! Status: COMPLETED
+Workflow result: 5 results, 5120 bytes
+```