Remove remaining status_id references after in_progress migration

- Remove Preload("Status") from worker handler and repositories
- Update seeds to use in_progress boolean instead of status_id
- Remove task_taskstatus table creation from lookup seeds
- Update documentation to reflect in_progress boolean pattern

Fixes notification worker error:
"Status: unsupported relations for schema Task"

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

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

docs/TASK_KANBAN_CATEGORIZATION.md

@@ -82,14 +82,14 @@ if task.NextDueDate == nil && len(task.Completions) > 0 {
 
 **Handler**: `InProgressHandler`
 
-**Condition**: `task.Status != nil && task.Status.Name == "In Progress"`
+**Condition**: `task.InProgress == true`
 
 **Result**: `in_progress_tasks`
 
-Tasks with the "In Progress" status are grouped together regardless of their due date. This allows users to see what's actively being worked on.
+Tasks marked as "In Progress" are grouped together regardless of their due date. This allows users to see what's actively being worked on.
 
 ```go
-if task.Status != nil && task.Status.Name == "In Progress" {
+if task.InProgress {
     return "in_progress_tasks"
 }
 ```
@@ -188,15 +188,14 @@ return "upcoming_tasks"
 This is by design - "In Progress" indicates active work, so the task should be visible there. However, this means:
 
 1. If a recurring task is marked "In Progress" and then completed
-2. The status MUST be reset to "Pending" after completion
+2. The `in_progress` flag MUST be reset to `false` after completion
 3. Otherwise, the task stays in "In Progress" instead of moving to "Upcoming"
 
 This is handled automatically in `TaskService.CreateCompletion()`:
 
 ```go
 if isRecurringTask {
-    pendingStatusID := uint(1)
-    task.StatusID = &pendingStatusID
+    task.InProgress = false
 }
 ```
 
@@ -246,8 +245,8 @@ Each column has associated metadata for UI rendering:
 import "github.com/treytartt/casera-api/internal/task/categorization"
 
 task := &models.Task{
-    DueDate: time.Now().AddDate(0, 0, 15), // 15 days from now
-    Status:  &models.TaskStatus{Name: "Pending"},
+    DueDate:    time.Now().AddDate(0, 0, 15), // 15 days from now
+    InProgress: false,
 }
 
 column := categorization.DetermineKanbanColumn(task, 30)
@@ -291,14 +290,14 @@ Key test scenarios:
 
 1. **Check `IsCancelled`**: Cancelled takes highest priority
 2. **Check `NextDueDate`**: For recurring tasks, this determines placement
-3. **Check `Status`**: "In Progress" overrides date-based categorization
+3. **Check `InProgress`**: `true` overrides date-based categorization
 4. **Check `Completions`**: Empty + nil NextDueDate = upcoming, not completed
 
 ### Recurring task not moving to Upcoming after completion?
 
 Verify that `CreateCompletion` is:
 1. Setting `NextDueDate` correctly
-2. Resetting `StatusID` to Pending (1)
+2. Resetting `InProgress` to `false`
 
 ### Task showing overdue but due date looks correct?