# [FEATURE] Visual differentiation for task timing

## Description
Tasks after today should be grayed out, past deadline should be emphasized.

## User Story
As a user, I want past-due tasks highlighted and future tasks dimmed so urgency is immediately visible.

## Technical Context
- Pure presentation logic in template
- Affects: `partials/todoist-tasks.html`, `partials/tasks-tab.html`
- Requires comparing task `due_date` against current date

## Test Strategy

### Unit Test (Red)
**File:** `internal/handlers/handlers_test.go`

Test helper function returns correct urgency class.

```go
func TestTaskUrgencyClass(t *testing.T) {
    tests := []struct {
        name     string
        dueDate  time.Time
        expected string
    }{
        {"overdue yesterday", yesterday, "overdue"},
        {"due today", today, "today"},
        {"due tomorrow", tomorrow, "future"},
        {"no due date", zeroTime, "none"},
    }
    // ...
}
```

### E2E Test (Red)
Assert CSS classes applied correctly to tasks based on due date.

## Proposed Approach

1. Add template helper or compute urgency class in handler
2. Return struct with `UrgencyClass` field for each task
3. Apply Tailwind classes based on urgency:
   - `text-red-600 font-bold` (overdue)
   - `text-inherit` or default (today)
   - `text-gray-400` (future)
4. Consider adding visual indicator icon (e.g., warning for overdue)

## Affected Components
- `internal/handlers/handlers.go`
- `internal/models/types.go` (if adding field to view model)
- `web/templates/partials/todoist-tasks.html`
- `web/templates/partials/tasks-tab.html`

## Definition of Done
- [ ] Overdue tasks visually emphasized (red/bold)
- [ ] Future tasks grayed out
- [ ] Today's tasks normal styling
- [ ] Unit tests for urgency calculation
- [ ] E2E test verifies correct classes applied