fix(activity): address code review feedback and improve timeline UX

- Extract shared timeAgo utility, remove duplicates from comment-card and issue-detail
- Remove unused replies prop from CommentCard
- Fix recursive delete to remove all descendant replies, not just direct children
- Improve formatActivity with human-readable status/priority labels and actor names
- Validate parent comment exists and belongs to same issue before creating reply
- Add priority_changed activity recording in activity listeners
- Fix activity SQL query to sort ASC (was DESC, then re-sorted in handler)
- Fix reply-input layout alignment and test submit button selector
- Minor: .gitignore additions, button dark mode aria-expanded fix

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/cmd/server/activity_listeners.go

@@ -59,6 +59,7 @@ func registerActivityListeners(bus *events.Bus, queries *db.Queries) {
 		}
 
 		statusChanged, _ := payload["status_changed"].(bool)
+		priorityChanged, _ := payload["priority_changed"].(bool)
 		assigneeChanged, _ := payload["assignee_changed"].(bool)
 		descriptionChanged, _ := payload["description_changed"].(bool)
 
@@ -84,6 +85,28 @@ func registerActivityListeners(bus *events.Bus, queries *db.Queries) {
 			}
 		}
 
+		if priorityChanged {
+			prevPriority, _ := payload["prev_priority"].(string)
+			details, _ := json.Marshal(map[string]string{
+				"from": prevPriority,
+				"to":   issue.Priority,
+			})
+			activity, err := queries.CreateActivity(ctx, db.CreateActivityParams{
+				WorkspaceID: parseUUID(issue.WorkspaceID),
+				IssueID:     parseUUID(issue.ID),
+				ActorType:   util.StrToText(e.ActorType),
+				ActorID:     parseUUID(e.ActorID),
+				Action:      "priority_changed",
+				Details:     details,
+			})
+			if err != nil {
+				slog.Error("activity: failed to record priority change",
+					"issue_id", issue.ID, "error", err)
+			} else {
+				publishActivityEvent(bus, e, activity)
+			}
+		}
+
 		if assigneeChanged {
 			prevAssigneeType, _ := payload["prev_assignee_type"].(*string)
 			prevAssigneeID, _ := payload["prev_assignee_id"].(*string)
@@ -119,6 +142,35 @@ func registerActivityListeners(bus *events.Bus, queries *db.Queries) {
 			}
 		}
 
+		if dueDateChanged, _ := payload["due_date_changed"].(bool); dueDateChanged {
+			prevDueDate := ""
+			if v, ok := payload["prev_due_date"].(*string); ok && v != nil {
+				prevDueDate = *v
+			}
+			newDueDate := ""
+			if issue.DueDate != nil {
+				newDueDate = *issue.DueDate
+			}
+			details, _ := json.Marshal(map[string]string{
+				"from": prevDueDate,
+				"to":   newDueDate,
+			})
+			activity, err := queries.CreateActivity(ctx, db.CreateActivityParams{
+				WorkspaceID: parseUUID(issue.WorkspaceID),
+				IssueID:     parseUUID(issue.ID),
+				ActorType:   util.StrToText(e.ActorType),
+				ActorID:     parseUUID(e.ActorID),
+				Action:      "due_date_changed",
+				Details:     details,
+			})
+			if err != nil {
+				slog.Error("activity: failed to record due date change",
+					"issue_id", issue.ID, "error", err)
+			} else {
+				publishActivityEvent(bus, e, activity)
+			}
+		}
+
 		if descriptionChanged {
 			activity, err := queries.CreateActivity(ctx, db.CreateActivityParams{
 				WorkspaceID: parseUUID(issue.WorkspaceID),
@@ -205,7 +257,7 @@ func publishActivityEvent(bus *events.Bus, original events.Event, activity db.Ac
 				"id":         util.UUIDToString(activity.ID),
 				"actor_type": actorType,
 				"actor_id":   util.UUIDToString(activity.ActorID),
-				"action":     &action,
+				"action":     action,
 				"details":    json.RawMessage(activity.Details),
 				"created_at": util.TimestampToString(activity.CreatedAt),
 			},