Implement Trello smart sorting by newest card activity

  - Update GetBoards SQL query with LEFT JOIN and GROUP BY
  - Sort by: 1) Has cards, 2) Newest card (MAX ID), 3) Board name
  - Update GetBoardsWithCards to match SQL sorting behavior
  - Leverage Trello ID chronological sortability (newer > older)
  - Active boards with recent activity appear first
  - All tests passing

  Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

1 files changed, 27 insertions, 1 deletions

diff --git a/internal/api/trello.go b/internal/api/trello.go
index b9391d6..c78ebc8 100644
--- a/internal/api/trello.go
+++ b/internal/api/trello.go
@@ -217,13 +217,39 @@ func (c *TrelloClient) GetBoardsWithCards(ctx context.Context) ([]models.Board,
 
 	wg.Wait()
 
-	// Sort boards: Non-empty boards first, then alphabetical by name
+	// Sort boards: Non-empty boards first, newest card activity, then alphabetical by name
+	// Trello card IDs are chronologically sortable (newer IDs > older IDs)
 	sort.Slice(boards, func(i, j int) bool {
 		hasCardsI := len(boards[i].Cards) > 0
 		hasCardsJ := len(boards[j].Cards) > 0
+
+		// 1. Prioritize boards with cards
 		if hasCardsI != hasCardsJ {
 			return hasCardsI // true (non-empty) comes before false
 		}
+
+		// 2. If both have cards, compare by newest card (max ID)
+		if hasCardsI && hasCardsJ {
+			maxIDI := ""
+			for _, card := range boards[i].Cards {
+				if maxIDI == "" || card.ID > maxIDI {
+					maxIDI = card.ID
+				}
+			}
+
+			maxIDJ := ""
+			for _, card := range boards[j].Cards {
+				if maxIDJ == "" || card.ID > maxIDJ {
+					maxIDJ = card.ID
+				}
+			}
+
+			if maxIDI != maxIDJ {
+				return maxIDI > maxIDJ // Newer (larger) ID comes first
+			}
+		}
+
+		// 3. Fallback to alphabetical by name
 		return boards[i].Name < boards[j].Name
 	})