Flows can now be taken off the engine and put back. Stopped state lives in a
runtime.json beside the flow, not in the flow document: the canvas autosaves
that document, so a stopped flow would otherwise start itself again on the
next edit. A stopped flow gets no subscriptions, schedules or webhooks, its
nodes are skipped by the scheduler, and running it answers 409. Pausing holds
a flow's nodes while its values keep arriving, so the canvas still shows what
is coming in.
Node code is user code and print is how it says things, so stdout is teed
through a contextvar sink active only during a node execution — one event per
execution, capped, so a chatty node cannot outrun the stream. A node that
fails sends its traceback the same way, trimmed to the author's own frames.
The dock gains a logs panel and a pause control; the dashboard replaces its
placeholder with what is running, stopped or failing; the edge inspector can
send the last message again.
Single-stepping is deferred and noted: the scheduler keeps no progress between
calls, so a step button would re-run the same node rather than advance.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Edits autosave to flow.draft.json and nodes.draft/ instead of the files the
engine reads, so the pipeline keeps running the published version until
someone publishes. Every save carries the version it was based on: a second
client editing the same flow is refused with 409 and offered the choice
between their version and its own, rather than silently overwriting.
Draft saves no longer rebuild the pipeline; validation and node status for a
draft come from a throwaway build that never touches live state.
Also fixes a latent bug where an empty state backend is falsy, so Pipeline
quietly built itself a second, private state and left message history empty.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
