Add honeycomb completion heatmap and data migration framework

- Add completion_summary endpoint data to residence detail response
- Track completed_from_column on task completions (overdue/due_soon/upcoming)
- Add GetCompletionSummary repo method with monthly aggregation
- Add one-time data migration framework (data_migrations table + registry)
- Add backfill migration to classify historical completions
- Add standalone backfill script for manual/dry-run usage

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/services/task_service.go

@@ -17,6 +17,7 @@ import (
 	"github.com/treytartt/honeydue-api/internal/dto/responses"
 	"github.com/treytartt/honeydue-api/internal/models"
 	"github.com/treytartt/honeydue-api/internal/repositories"
+	"github.com/treytartt/honeydue-api/internal/task/categorization"
 )
 
 // Task-related errors (DEPRECATED - kept for reference, use apperrors instead)
@@ -551,13 +552,18 @@ func (s *TaskService) CreateCompletion(req *requests.CreateTaskCompletionRequest
 		completedAt = *req.CompletedAt
 	}
 
+	// Capture the kanban column BEFORE mutating NextDueDate/InProgress,
+	// so we know what state the task was in when the user completed it.
+	completedFromColumn := categorization.DetermineKanbanColumnWithTime(task, 30, now)
+
 	completion := &models.TaskCompletion{
-		TaskID:        req.TaskID,
-		CompletedByID: userID,
-		CompletedAt:   completedAt,
-		Notes:         req.Notes,
-		ActualCost:    req.ActualCost,
-		Rating:        req.Rating,
+		TaskID:              req.TaskID,
+		CompletedByID:       userID,
+		CompletedAt:         completedAt,
+		Notes:               req.Notes,
+		ActualCost:          req.ActualCost,
+		Rating:              req.Rating,
+		CompletedFromColumn: completedFromColumn,
 	}
 
 	// Determine interval days for NextDueDate calculation before entering the transaction.
@@ -680,11 +686,15 @@ func (s *TaskService) QuickComplete(taskID uint, userID uint) error {
 
 	completedAt := time.Now().UTC()
 
+	// Capture kanban column before state mutation
+	completedFromColumn := categorization.DetermineKanbanColumn(task, 30)
+
 	completion := &models.TaskCompletion{
-		TaskID:        taskID,
-		CompletedByID: userID,
-		CompletedAt:   completedAt,
-		Notes:         "Completed from widget",
+		TaskID:              taskID,
+		CompletedByID:       userID,
+		CompletedAt:         completedAt,
+		Notes:               "Completed from widget",
+		CompletedFromColumn: completedFromColumn,
 	}
 
 	if err := s.taskRepo.CreateCompletion(completion); err != nil {