feat(author): Add Cancel Job button to Author module

Added a "Cancel Job" button to the Author module top bar that:
- Appears only when an Author job is currently running
- Uses DangerImportance styling for clear visual indication
- Cancels the running author job when clicked
- Hides automatically when no author job is running

This addresses the user's request for cancel buttons in every module
where it's relevant. The button provides immediate job cancellation
without needing to navigate to the queue view.

author_module.go

@@ -161,7 +161,18 @@ func buildAuthorView(state *appState) fyne.CanvasObject {
 	})
 	clearCompletedBtn.Importance = widget.LowImportance
 
-	topBar := ui.TintedBar(authorColor, container.NewHBox(backBtn, layout.NewSpacer(), clearCompletedBtn, queueBtn))
+	cancelBtn := widget.NewButton("Cancel Job", func() {
+		if state.jobQueue != nil {
+			if job := state.jobQueue.CurrentRunning(); job != nil && job.Type == queue.JobTypeAuthor {
+				state.jobQueue.Cancel(job.ID)
+			}
+		}
+	})
+	cancelBtn.Importance = widget.DangerImportance
+	state.authorCancelBtn = cancelBtn
+	state.updateAuthorCancelButton()
+
+	topBar := ui.TintedBar(authorColor, container.NewHBox(backBtn, layout.NewSpacer(), cancelBtn, clearCompletedBtn, queueBtn))
 	bottomBar := moduleFooter(authorColor, layout.NewSpacer(), state.statsBar)
 
 	tabs := container.NewAppTabs(
@@ -1397,6 +1408,22 @@ func (s *appState) setAuthorProgress(percent float64) {
 	}
 }
 
+func (s *appState) updateAuthorCancelButton() {
+	if s.authorCancelBtn == nil {
+		return
+	}
+	if s.jobQueue == nil {
+		s.authorCancelBtn.Hide()
+		return
+	}
+	job := s.jobQueue.CurrentRunning()
+	if job != nil && job.Type == queue.JobTypeAuthor {
+		s.authorCancelBtn.Show()
+	} else {
+		s.authorCancelBtn.Hide()
+	}
+}
+
 func (s *appState) startAuthorGeneration(startNow bool) {
 	if s.authorVideoTSPath != "" {
 		title := authorOutputTitle(s)

main.go

@@ -974,6 +974,7 @@ type appState struct {
 	authorProgress        float64
 	authorProgressBar     *widget.ProgressBar
 	authorStatusLabel     *widget.Label
+	authorCancelBtn       *widget.Button
 	authorVideoTSPath     string
 
 	// Rip module state