New run: start a run from the app, on the working copy

The site promises simulated inputs and mocked sensor values, and nothing in
the app was that. A run already is: the values are the caller's, the state is
the run's own namespace, and nothing it computes reaches the live flow. What
was missing was a screen to do it from, and the draft flag being honoured.

`/runs/new` is a flow, a field per declared input, a seed and Run; `/runs`
stays the log. A comma-separated list in a number field expands into the grid
`fluksio sweep --param` builds and goes to the sweep route, so launching one
no longer needs a terminal. Only numbers split: a comma in a string is
content, and one in JSON is syntax.

`RunCreate.draft` was validated at submit and dropped before the run
executed, so "try the working copy" ran the published one. `Run.draft` is a
column now, the driver reads the same copy the submit checked, and a retry
carries it. `FlowSummary.mode` came with it so the rail can say which flows
are batch before one is picked.

Also here: a Retry button on a finished run, which the route has always had
and the UI never did, and parameter cells truncated to their column with the
full value on hover.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013TTfoK82awm8wvxXhHz3XF

backend/fluksio/models.py

@@ -374,6 +374,9 @@ class Run(SQLModel, table=True):
     cause: str = Field(default="api", max_length=32)
     #: Re-execute every node, whatever the stage cache holds for it.
     no_cache: bool = False
+    #: Run the unpublished working copy rather than what is published. Read
+    #: again when the run starts, so a draft published in between is what runs.
+    draft: bool = False
     #: queued, running, ok, error, cancelled or abandoned.
     status: str = Field(default="queued", index=True, max_length=16)
     #: Why it is where it is: what it waits for, or what went wrong.