fix(desktop): show workflow list trigger failures

[SSBrouhard]

Choosing Trigger from a workflow card currently fails silently when the request is rejected. The menu closes, but there is no indication that the workflow could not start.

This change shows Couldn’t start workflow with the error returned by the request. The workflow card stays available so the user can retry. Successful triggers keep their existing behavior. This reports a failure to start a run; it does not diagnose failures inside a running workflow.

Checked for overlap

Checked open Buzz issues and PRs on October 10, 2026, using searches for workflow triggers, errors, toasts, and WorkflowsView, plus the full open PR title list and workflow-related open issue titles. No matching report or fix was found for rejected triggers from the workflow list.

The closest changes cover different actions: #4292 keeps save errors visible, #4293 handles webhook permissions while creating or editing a workflow, and #5888 restores workflows missing from the list. This PR only handles the list’s Trigger action.

Validation

• Reproduced the silent failure through the actual workflow-card menu in the desktop app’s mock test environment. The regression test failed on the original code because no error notification appeared.
• With the fix, the test verifies the error title and reason, no run created by the rejected request, and a successful retry after the failure is cleared.
• Both the new regression test and the existing successful-trigger test pass.
• Desktop type checks, lint/format checks, and the repository file-size check pass.
• All 6,989 desktop tests pass.
• The full repository gate, just ci, passes.

Human test

Use a harmless test workflow. Open Workflows, open its card’s actions menu, and choose Trigger while the trigger request is rejected (for example, with the relay unavailable). Confirm the error appears with its reason. Restore the connection and trigger again; the run should start normally.

The author confirmed the human test is complete on October 10, 2026. The code review and agent-run UI tests are also complete. The full repository checks pass. The readiness checklist is complete.

buzz-review-completed

Before and after

Same rejected trigger request, using test data only.

Before: the menu closes without any failure feedback.

After: the failure and its reason are visible.

[github-actions]

🔐 Codex Security Review

Status: review required for the current range.

The current range is 326e2301cb4b1edcb8a72d01ac4b19a83545365f...b0ed1e35a713428ca9fde8881ea098efeb49972e.
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[SSBrouhard]

Screenshots

[SSBrouhard]

Reviewed against Buzz’s product and testing guidance. The change uses the existing error notification pattern and preserves the successful trigger flow. The regression test exercises the actual card menu and request path, verifies rejection feedback, and confirms retry succeeds. No blocking findings. Minimalism, elegance, and correctness each meet the repository’s 9/10 review bar.

The author confirmed the human test is complete. The full local gate (just ci) and focused UI tests pass; buzz-review-completed has been added.