Improve cartoon workflow next-action CTA clarity

[realproject7]

Context

While testing plotlink-ows@1.2.94 on the cartoon story god-cell, the current workflow guidance is easy to miss. The primary next step is rendered as small inline text (Next: Review cuts and start lettering) plus a nearby button whose label repeats the action text. The same action also appears in multiple file/tab contexts, which makes it unclear what the operator should do next.

Problem

The UI does not make the next task visually or behaviorally obvious enough. The next action should be a consistent, prominent control instead of a small status row with duplicated copy.

Proposed UX

Add a persistent cartoon workflow Next Action area, preferably anchored in the lower-right of the workflow panel or otherwise consistently placed in the right pane.

The UI should show:

• A clear text summary: Next: Review cuts and start lettering
• A single prominent button labeled Next Action
• Button size should be at least comparable to the left sidebar + New Story button
• The same button label should be used across workflow tabs and navigation surfaces: Next Action
• Avoid duplicating the full action text inside both the summary and the button

Acceptance Criteria

• The current next step is always visible from the cartoon workflow panel without hunting through status rows.
• The primary CTA uses the standardized label Next Action.
• The action summary and button label are not duplicated.
• The CTA is visually prominent enough to be the obvious next step, at least comparable in size/weight to + New Story.
• The CTA appears consistently on Progress, Whitepaper, Genesis / Ep 1, Episodes, and Publish contexts when a next action exists.
• When no next action is available, the UI shows a clear completed/blocked state instead of an inactive ambiguous button.
• Existing workflow state calculations continue to drive the target action; this issue should not fork a second workflow-decision system.

Notes

Observed on god-cell where clean images are ready and the next workflow action is lettering. This should generalize to other cartoon workflow stages.

[realproject7]

Closed by PR #490.