Migrate from Gin to Echo framework and add comprehensive integration tests

Major changes:
- Migrate all handlers from Gin to Echo framework
- Add new apperrors, echohelpers, and validator packages
- Update middleware for Echo compatibility
- Add ArchivedHandler to task categorization chain (archived tasks go to cancelled_tasks column)
- Add 6 new integration tests:
  - RecurringTaskLifecycle: NextDueDate advancement for weekly/monthly tasks
  - MultiUserSharing: Complex sharing with user removal
  - TaskStateTransitions: All state transitions and kanban column changes
  - DateBoundaryEdgeCases: Threshold boundary testing
  - CascadeOperations: Residence deletion cascade effects
  - MultiUserOperations: Shared residence collaboration
- Add single-purpose repository functions for kanban columns (GetOverdueTasks, GetDueSoonTasks, etc.)
- Fix RemoveUser route param mismatch (userId -> user_id)
- Fix determineExpectedColumn helper to correctly prioritize in_progress over overdue

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

internal/task/predicates/predicates.go

@@ -91,16 +91,18 @@ func EffectiveDate(task *models.Task) *time.Time {
 	return task.DueDate
 }
 
-// IsOverdue returns true if the task's effective date is in the past.
+// IsOverdue returns true if the task's effective date is before today.
 //
 // A task is overdue when:
 //   - It has an effective date (NextDueDate or DueDate)
-//   - That date is before the given time
+//   - That date is before the start of the current day
 //   - The task is not completed, cancelled, or archived
 //
+// Note: A task due "today" is NOT overdue. It becomes overdue tomorrow.
+//
 // SQL equivalent (in scopes.go ScopeOverdue):
 //
-//	COALESCE(next_due_date, due_date) < ?
+//	COALESCE(next_due_date, due_date) < DATE_TRUNC('day', ?)
 //	AND NOT (next_due_date IS NULL AND EXISTS completion)
 //	AND is_cancelled = false AND is_archived = false
 func IsOverdue(task *models.Task, now time.Time) bool {
@@ -111,20 +113,25 @@ func IsOverdue(task *models.Task, now time.Time) bool {
 	if effectiveDate == nil {
 		return false
 	}
-	return effectiveDate.Before(now)
+	// Compare against start of today, not current time
+	// A task due "today" should not be overdue until tomorrow
+	startOfDay := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
+	return effectiveDate.Before(startOfDay)
 }
 
 // IsDueSoon returns true if the task's effective date is within the threshold.
 //
 // A task is "due soon" when:
 //   - It has an effective date (NextDueDate or DueDate)
-//   - That date is >= now AND < (now + daysThreshold)
+//   - That date is >= start of today AND < start of (today + daysThreshold)
 //   - The task is not completed, cancelled, archived, or already overdue
 //
+// Note: Uses start of day for comparisons so tasks due "today" are included.
+//
 // SQL equivalent (in scopes.go ScopeDueSoon):
 //
-//	COALESCE(next_due_date, due_date) >= ?
-//	AND COALESCE(next_due_date, due_date) < ?
+//	COALESCE(next_due_date, due_date) >= DATE_TRUNC('day', ?)
+//	AND COALESCE(next_due_date, due_date) < DATE_TRUNC('day', ?) + interval 'N days'
 //	AND NOT (next_due_date IS NULL AND EXISTS completion)
 //	AND is_cancelled = false AND is_archived = false
 func IsDueSoon(task *models.Task, now time.Time, daysThreshold int) bool {
@@ -135,18 +142,22 @@ func IsDueSoon(task *models.Task, now time.Time, daysThreshold int) bool {
 	if effectiveDate == nil {
 		return false
 	}
-	threshold := now.AddDate(0, 0, daysThreshold)
-	// Due soon = not overdue AND before threshold
-	return !effectiveDate.Before(now) && effectiveDate.Before(threshold)
+	// Use start of day for comparisons
+	startOfDay := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
+	threshold := startOfDay.AddDate(0, 0, daysThreshold)
+	// Due soon = not overdue (>= start of today) AND before threshold
+	return !effectiveDate.Before(startOfDay) && effectiveDate.Before(threshold)
 }
 
 // IsUpcoming returns true if the task is due after the threshold or has no due date.
 //
 // A task is "upcoming" when:
 //   - It has no effective date, OR
-//   - Its effective date is >= (now + daysThreshold)
+//   - Its effective date is >= start of (today + daysThreshold)
 //   - The task is not completed, cancelled, or archived
 //
+// Note: Uses start of day for comparisons for consistency with other predicates.
+//
 // This is the default category for tasks that don't match other criteria.
 func IsUpcoming(task *models.Task, now time.Time, daysThreshold int) bool {
 	if !IsActive(task) || IsCompleted(task) {
@@ -156,7 +167,9 @@ func IsUpcoming(task *models.Task, now time.Time, daysThreshold int) bool {
 	if effectiveDate == nil {
 		return true // No due date = upcoming
 	}
-	threshold := now.AddDate(0, 0, daysThreshold)
+	// Use start of day for comparisons
+	startOfDay := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
+	threshold := startOfDay.AddDate(0, 0, daysThreshold)
 	return !effectiveDate.Before(threshold)
 }
 

internal/task/predicates/predicates_test.go

@@ -187,6 +187,8 @@ func TestIsOverdue(t *testing.T) {
 	now := time.Now().UTC()
 	yesterday := now.AddDate(0, 0, -1)
 	tomorrow := now.AddDate(0, 0, 1)
+	// Start of today - this is what a DATE column stores (midnight)
+	startOfToday := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
 
 	tests := []struct {
 		name     string
@@ -216,6 +218,17 @@ func TestIsOverdue(t *testing.T) {
 			now:      now,
 			expected: false,
 		},
+		{
+			name: "not overdue: task due today (start of day)",
+			task: &models.Task{
+				NextDueDate: timePtr(startOfToday),
+				IsCancelled: false,
+				IsArchived:  false,
+				Completions: []models.TaskCompletion{},
+			},
+			now:      now, // Current time during the day
+			expected: false,
+		},
 		{
 			name: "not overdue: cancelled task",
 			task: &models.Task{
@@ -291,6 +304,8 @@ func TestIsDueSoon(t *testing.T) {
 	yesterday := now.AddDate(0, 0, -1)
 	in5Days := now.AddDate(0, 0, 5)
 	in60Days := now.AddDate(0, 0, 60)
+	// Start of today - this is what a DATE column stores (midnight)
+	startOfToday := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
 
 	tests := []struct {
 		name          string
@@ -311,6 +326,18 @@ func TestIsDueSoon(t *testing.T) {
 			daysThreshold: 30,
 			expected:      true,
 		},
+		{
+			name: "due soon: task due today (start of day)",
+			task: &models.Task{
+				NextDueDate: timePtr(startOfToday),
+				IsCancelled: false,
+				IsArchived:  false,
+				Completions: []models.TaskCompletion{},
+			},
+			now:           now, // Current time during the day
+			daysThreshold: 30,
+			expected:      true,
+		},
 		{
 			name: "not due soon: beyond threshold",
 			task: &models.Task{