SDK: artifacts work outside a node, run --follow prints status and queue waits, fluksio cancel

save_artifact/load_artifact outside a node use the worker's own store code in
$FLUKSIO_ARTIFACT_DIR or <tmp>/fluksio-artifacts, so a node can be called by
hand. --follow prints status changes and each node's resource wait; the
placer's waiting snapshot now carries the run. fluksio cancel <run>...

docs/getting-started/data-science.md

@@ -113,7 +113,8 @@ fluksio run train --lr 0.1 --epochs 20 --follow
 
 `sync` uploads the flow and generates node code that imports your functions.
 Keep the project files available to the engine. Later `run` commands sync
-edits before submitting; `--follow` waits and prints metrics as they arrive.
+edits before submitting. `--follow` waits and prints metrics as they arrive,
+along with status changes and what a queued node is waiting for.
 This run should finish with `final_loss` around `0.1353` and `score` around
 `0.8647`.
 
@@ -155,9 +156,10 @@ Pass either list to `pandas.DataFrame` if you use pandas.
 
 ## Bring your own experiment
 
-Replace the toy calculation in `fit` with your training code. Keep ordinary
-Python helpers separate from artifact storage so you can still test them
-without an engine: `save_artifact` and `load_artifact` work only inside nodes.
+Replace the toy calculation in `fit` with your training code. You can call a
+node directly to test it without an engine: `save_artifact` and
+`load_artifact` then use a folder under the temporary directory, and `emit`
+does nothing.
 The public repository's `examples/myresearch/` package shows this pattern
 across several files.