PromptManager: Stages tab Save, Create, and Delete lack success toasts and Create fails to navigate to the new stage

[atomantic]

Problem

In client/src/pages/PromptManager.jsx, stage mutation flows lack success notifications, and the stage creation workflow fails to select or reveal the newly created stage:

1. Save stage lacks success toast (client/src/pages/PromptManager.jsx:202-208):

   const ok = await savePrompt(selectedStage, payload, { silent: true })
     .then(() => true)
     .catch((err) => { toast.error('Failed to save stage: ' + err.message); return false; });
   if (!ok) { setSaving(false); return; }
   setSaving(false);
   await loadData();

   { silent: true } suppresses the default toast from request(). While failures toast via toast.error, successful saves call no toast. The Save button simply re-enables. (In contrast, saveJobSkill in line 370 calls toast.success('Job skill saved'), added in [UX Audit] [PromptManager] Job skill save failures are swallowed silently with no user error toast #3937).

2. Create stage neither toasts nor selects the new stage (client/src/pages/PromptManager.jsx:270-287):

   const ok = await createPrompt(payload, { silent: true })
     .then(() => true)
     .catch((err) => { setSaving(false); toast.error(err.message || 'Failed to create stage'); return false; });
   if (!ok) return;
   
   setSaving(false);
   setCreatingStage(false);
   setNewStageForm({ ... });
   await loadData();

   When createPrompt succeeds, it returns { success: true, stageName }. On success, no toast is displayed, the modal closes, and setSelectedStage(payload.stageName) is NEVER called. The user remains parked on whatever stage was previously selected (or empty). Because the 120+ stages are partitioned across collapsible accordion groups, the newly created stage is buried out of sight in a collapsed group.

3. Delete stage lacks success toast (client/src/pages/PromptManager.jsx:308-317):
   deletePrompt resolves, the modal closes, and selection clears if matching, but no confirmation toast confirms the deletion.

Trigger

1. In /prompts (Stages tab), edit a template or config and click "Save". The button disables and re-enables; no notification appears.
2. Click "+" ("New Stage"), fill out key my-stage and name Pipeline — My Stage, and click "Create Stage". The modal closes, no notification appears, and the editor continues displaying the old stage or placeholder while the new stage sits unseen inside a collapsed group.
3. Click "Delete", confirm in the modal. The modal closes with no confirmation feedback.

Impact

• Invisible mutation state: Users cannot distinguish a completed server save from a dropped or lagged request.
• Dead end / disorientation: Creating a stage leaves the user searching through 120+ stages and accordions just to locate and begin editing the template of the stage they just created.

Fix

1. In client/src/pages/PromptManager.jsx:
   • In saveStage: on success, call toast.success(Stage "${stages[selectedStage]?.name || selectedStage}" saved).
   • In createStage: on success, close the modal, reset the form, call setSelectedStage(payload.stageName) to deep-link to the new stage (which automatically triggers selectedGroupKey to expand its parent accordion group), and call toast.success(Stage "${payload.name || payload.stageName}" created).
   • In confirmDeleteStage: on success, call toast.success(Stage "${stageName}" deleted).
2. Rejected alternative: Leaving stage creation unselected and relying on manual user search. Rejected per client/src/AGENTS.md ("ID-based deep linking for every selectable UI element - any view that opens/selects a specific record MUST encode that selection in the URL").

Dispatch rationale: model:light + effort:low — mechanical addition of success toasts and setting selectedStage on creation, with companion unit test assertions in PromptManager.test.jsx.

Files to touch:

• client/src/pages/PromptManager.jsx
• client/src/pages/PromptManager.test.jsx

Acceptance criteria

• Saving a prompt stage displays a success toast confirming the stage was saved.
• Creating a new prompt stage displays a success toast with the stage name.
• Creating a new prompt stage automatically selects it in the URL (?stage=<stageName>) and expands its parent group accordion in the sidebar list so the editor immediately opens the new stage.
• Deleting a prompt stage displays a success toast confirming deletion.
• All existing test suites in PromptManager.test.jsx pass.

[Bryandero98]

I'd like to work on this — could you assign it to me?

[Bryandero98]

Fixed and merged in #6108.

[atomantic]

Already fixed on main — verified against the current tree rather than taken on report.

client/src/pages/PromptManager.jsx now covers all four acceptance criteria:

• saveStage — toast.success(Stage "${openStageLabel}" saved)
• createStage — toast.success(...) plus switchStage(payload.stageName), which writes ?stage=<key> to the URL; the selectedGroupKey effect then expands the new stage's accordion group once loadData() lands.
• confirmDeleteStage — toast.success(Stage "${stageName}" deleted)

client/src/pages/PromptManager.test.jsx carries the matching assertions, including a deep-link check (expect(currentSearch()).toContain('stage=my-new-stage')). Full file: 63 tests passing.

Evidence: PR #6108, merge commit 1fd0ab3a7a4072ade434e7d28fca71cb2bbd7cab.

Closing as completed; no further change needed.