ai-agents-subgraph-command-end-when-a-subgraph-node-returns-command-goto-end-upda-bf2f34d8

THEN Modify the `apply_writes` function in `langgraph/pregel/algo.py` to skip the warning for channels matching `branch:to:__end__`. This treats END channel writes as a special case that doesn't require explicit channel registration, preventing the spurious warning while preserving all existing functionality.

In `apply_writes`, add a condition to skip the warning if the unknown channel matches `branch:to:{END}`. For example:

```python
from langgraph.constants import END

unknown_channel = ...
if unknown_channel == f'branch:to:{END}':
    continue  # skip warning
```