Onboarding: template backlink, bulk-create endpoint, climate-region scoring

Clients that send users through a multi-task onboarding step no longer
loop N POST /api/tasks/ calls and no longer create "orphan" tasks with
no reference to the TaskTemplate they came from.

Task model
- New task_template_id column + GORM FK (migration 000016)
- CreateTaskRequest.template_id, TaskResponse.template_id
- task_service.CreateTask persists the backlink

Bulk endpoint
- POST /api/tasks/bulk/ — 1-50 tasks in a single transaction,
  returns every created row + TotalSummary. Single residence access
  check, per-entry residence_id is overridden with batch value
- task_handler.BulkCreateTasks + task_service.BulkCreateTasks using
  db.Transaction; task_repo.CreateTx + FindByIDTx helpers

Climate-region scoring
- templateConditions gains ClimateRegionID; suggestion_service scores
  residence.PostalCode -> ZipToState -> GetClimateRegionIDByState against
  the template's conditions JSON (no penalty on mismatch / unknown ZIP)
- regionMatchBonus 0.35, totalProfileFields 14 -> 15
- Standalone GET /api/tasks/templates/by-region/ removed; legacy
  task_tasktemplate_regions many-to-many dropped (migration 000017).
  Region affinity now lives entirely in the template's conditions JSON

Tests
- +11 cases across task_service_test, task_handler_test, suggestion_
  service_test: template_id persistence, bulk rollback + cap + auth,
  region match / mismatch / no-ZIP / unknown-ZIP / stacks-with-others

Docs
- docs/openapi.yaml: /tasks/bulk/ + BulkCreateTasks schemas, template_id
  on TaskResponse + CreateTaskRequest, /templates/by-region/ removed

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/repositories/task_repo.go

@@ -355,6 +355,27 @@ func (r *TaskRepository) Create(task *models.Task) error {
 	return r.db.Create(task).Error
 }
 
+// CreateTx creates a new task within an existing transaction. Used by
+// bulk-create flows where multiple inserts must succeed or fail together.
+func (r *TaskRepository) CreateTx(tx *gorm.DB, task *models.Task) error {
+	return tx.Create(task).Error
+}
+
+// FindByIDTx loads a task within an existing transaction. Preloads only the
+// fields the bulk-create response needs (CreatedBy, AssignedTo). Category /
+// Priority / Frequency are resolved client-side from the lookup cache, so
+// we skip them here to match the FindByResidence preload set.
+func (r *TaskRepository) FindByIDTx(tx *gorm.DB, id uint) (*models.Task, error) {
+	var task models.Task
+	err := tx.Preload("CreatedBy").
+		Preload("AssignedTo").
+		First(&task, id).Error
+	if err != nil {
+		return nil, err
+	}
+	return &task, nil
+}
+
 // Update updates a task with optimistic locking.
 // The update only succeeds if the task's version in the database matches the expected version.
 // On success, the local task.Version is incremented to reflect the new version.

internal/repositories/task_template_repo.go

@@ -104,20 +104,6 @@ func (r *TaskTemplateRepository) Count() (int64, error) {
 	return count, err
 }
 
-// GetByRegion returns active templates associated with a specific climate region
-func (r *TaskTemplateRepository) GetByRegion(regionID uint) ([]models.TaskTemplate, error) {
-	var templates []models.TaskTemplate
-	err := r.db.
-		Preload("Category").
-		Preload("Frequency").
-		Preload("Regions").
-		Joins("JOIN task_tasktemplate_regions ON task_tasktemplate_regions.task_template_id = task_tasktemplate.id").
-		Where("task_tasktemplate_regions.climate_region_id = ? AND task_tasktemplate.is_active = ?", regionID, true).
-		Order("task_tasktemplate.display_order ASC, task_tasktemplate.title ASC").
-		Find(&templates).Error
-	return templates, err
-}
-
 // GetGroupedByCategory returns templates grouped by category name
 func (r *TaskTemplateRepository) GetGroupedByCategory() (map[string][]models.TaskTemplate, error) {
 	templates, err := r.GetAll()

internal/repositories/task_template_repo_test.go

@@ -185,33 +185,6 @@ func TestTaskTemplateRepository_Count(t *testing.T) {
 	assert.Equal(t, int64(2), count) // Only active
 }
 
-func TestTaskTemplateRepository_GetByRegion(t *testing.T) {
-	t.Skip("requires PostgreSQL: SQLite cannot scan jsonb default into json.RawMessage")
-	db := testutil.SetupTestDB(t)
-	repo := NewTaskTemplateRepository(db)
-
-	// Create a climate region
-	region := &models.ClimateRegion{Name: "Hot-Humid", ZoneNumber: 1, IsActive: true}
-	require.NoError(t, db.Create(region).Error)
-
-	// Create template with region association
-	tmpl := &models.TaskTemplate{Title: "Regional Task", IsActive: true}
-	require.NoError(t, db.Create(tmpl).Error)
-
-	// Associate template with region via join table
-	err := db.Exec("INSERT INTO task_tasktemplate_regions (task_template_id, climate_region_id) VALUES (?, ?)", tmpl.ID, region.ID).Error
-	require.NoError(t, err)
-
-	// Create template without region
-	tmpl2 := &models.TaskTemplate{Title: "Non-Regional Task", IsActive: true}
-	require.NoError(t, db.Create(tmpl2).Error)
-
-	templates, err := repo.GetByRegion(region.ID)
-	require.NoError(t, err)
-	assert.Len(t, templates, 1)
-	assert.Equal(t, "Regional Task", templates[0].Title)
-}
-
 func TestTaskTemplateRepository_GetGroupedByCategory(t *testing.T) {
 	t.Skip("requires PostgreSQL: SQLite cannot scan jsonb default into json.RawMessage")
 	db := testutil.SetupTestDB(t)