feat(gradebook): add gradebook with column picker, CSV export, grade links & sorting

Introduce the course gradebook: a frozen-column table of students × assessments
with a column picker, CSV export, and per-grade links into submissions.

Gradebook table
- Page with TanStack-backed table: pinned checkbox + Name columns, sticky
  header and Max Marks rows, frozen-column border seams that survive sticky
  scroll compositing.
- Column picker (assessments grouped by tab/category) and CSV export of the
  selected columns; empty-state hint when no data columns are chosen.
- External ID column, shown when any student has one.
- Grade cells link to the student's submission; a dismissible GradeLinkHint
  banner explains the affordance (persisted per-user via useDismissibleOnce).
- "Search students" global search.
- Default sort with name ascending, null/undefined at bottom of sort regardless of order

Shared table builder
- getColumnCanGlobalFilter is gated on column visibility ("search what you
  see"): hiding a column via the picker removes it from search, and the
  nullable-first-row type sniff is bypassed. Affects all TanStack tables.

Backend
- Gradebook controller, ability and course component; index JSON serializes
  students, assessments, submissions (with submissionId) and gamification.
- Submission grade query also selects the submission id for grade links.

- Remove the redundant ScoreAssessmentSummary download from Statistics.

Author: LWS49

.circleci/config.yml

@@ -119,6 +119,7 @@ commands:
           command: yarn build:test
           environment:
             AVAILABLE_CPUS: 4
+            NODE_OPTIONS: --max-old-space-size=4096
 
       - save_cache:
           paths:

app/controllers/components/course/gradebook_component.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+class Course::GradebookComponent < SimpleDelegator
+  include Course::ControllerComponentHost::Component
+
+  def self.display_name
+    'Gradebook'
+  end
+
+  def sidebar_items
+    return [] unless can?(:read_gradebook, current_course)
+
+    [
+      {
+        key: self.class.key,
+        icon: :gradebook,
+        type: :normal,
+        weight: 9,
+        path: course_gradebook_path(current_course)
+      }
+    ]
+  end
+end

app/controllers/course/gradebook_controller.rb

@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+class Course::GradebookController < Course::ComponentController
+  before_action :authorize_read_gradebook!
+  before_action :preload_levels, only: [:index]
+
+  def index
+    respond_to do |format|
+      format.json do
+        @published_assessments = fetch_published_assessments
+        @categories, @tabs = fetch_categories_and_tabs
+        @students = fetch_students
+        assessment_ids = @published_assessments.pluck(:id)
+        @assessment_max_grades = Course::Assessment.max_grades(assessment_ids)
+        @submissions = Course::Assessment::Submission.grade_summary(
+          student_ids: @students.map(&:user_id),
+          assessment_ids: assessment_ids
+        )
+      end
+    end
+  end
+
+  private
+
+  def authorize_read_gradebook!
+    authorize! :read_gradebook, current_course
+  end
+
+  def component
+    current_component_host[:course_gradebook_component]
+  end
+
+  def fetch_categories_and_tabs
+    tabs = @published_assessments.map(&:tab).uniq(&:id)
+    [tabs.map(&:category).uniq(&:id), tabs]
+  end
+
+  def fetch_students
+    current_course.course_users.students.without_phantom_users.
+      calculated(:experience_points).includes(user: :emails).to_a
+  end
+
+  def fetch_published_assessments
+    current_course.assessments.
+      published.
+      includes(tab: :category).
+      joins(tab: :category).
+      reorder('course_assessment_categories.weight, course_assessment_tabs.weight, course_assessments.id')
+  end
+
+  # Pre-loads course levels to avoid N+1 queries when each course_user.level_number is rendered.
+  # level_number is derived, not an association (it buckets EXP against course.levels), so it
+  # can't be added to fetch_students' includes. See Course::LevelsConcern#level_for.
+  def preload_levels
+    current_course.levels.to_a
+  end
+end

app/controllers/course/statistics/aggregate_controller.rb

@@ -47,13 +47,6 @@ def activity_get_help
     @course_user_hash = current_course.course_users.index_by(&:user_id)
   end
 
-  def download_score_summary
-    job = Course::Statistics::AssessmentsScoreSummaryDownloadJob.
-          perform_later(current_course, params[:assessment_ids]).job
-
-    render partial: 'jobs/submitted', locals: { job: job }
-  end
-
   private
 
   def sanitize_date_range(start_at_param, end_at_param)

app/jobs/course/statistics/assessments_score_summary_download_job.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+module Course::GradebookAbilityComponent
+  include AbilityHost::Component
+
+  def define_permissions
+    can :read_gradebook, Course, id: course.id if course_user&.staff?
+    super
+  end
+end

app/models/components/course/gradebook_ability_component.rb

@@ -160,6 +160,22 @@ def self.use_relative_model_naming?
     true
   end
 
+  # Returns a hash of assessment_id => max_grade (sum of question maximum_grades).
+  def self.max_grades(assessment_ids)
+    return {} if assessment_ids.empty?
+
+    rows = find_by_sql(
+      sanitize_sql_array([<<-SQL.squish, assessment_ids])
+        SELECT cqa.assessment_id, COALESCE(SUM(caq.maximum_grade), 0) AS max_grade
+        FROM course_question_assessments cqa
+        JOIN course_assessment_questions caq ON caq.id = cqa.question_id
+        WHERE cqa.assessment_id IN (?)
+        GROUP BY cqa.assessment_id
+      SQL
+    )
+    rows.to_h { |row| [row.assessment_id, row.max_grade.to_f] }
+  end
+
   def to_partial_path
     'course/assessment/assessments/assessment'
   end

app/models/course/assessment.rb

@@ -323,6 +323,27 @@ def self.on_dependent_status_change(answer)
     answer.submission.last_graded_time = Time.now
   end
 
+  # Returns an array of submission rows for the given students and assessments.
+  # Each row has: student_id (creator_id), assessment_id, grade (float).
+  # Only graded/published submissions are included.
+  def self.grade_summary(student_ids:, assessment_ids:)
+    return [] if student_ids.empty? || assessment_ids.empty?
+
+    find_by_sql(
+      sanitize_sql_array([<<-SQL.squish, student_ids, assessment_ids])
+        SELECT cas.creator_id AS student_id, cas.assessment_id,
+               cas.id AS submission_id, SUM(caa.grade) AS grade
+        FROM course_assessment_submissions cas
+        JOIN course_assessment_answers caa ON caa.submission_id = cas.id
+        WHERE cas.creator_id IN (?)
+          AND cas.assessment_id IN (?)
+          AND cas.workflow_state IN ('graded', 'published')
+          AND caa.current_answer = TRUE
+        GROUP BY cas.creator_id, cas.assessment_id, cas.id
+      SQL
+    )
+  end
+
   private
 
   # Queues the submission for auto grading, after the submission has changed to the submitted state.

app/models/course/assessment/submission.rb

@@ -4,6 +4,7 @@ json.courseUrl course_path(current_course)
 json.courseLogoUrl url_to_course_logo(current_course)
 json.courseUserUrl url_to_user_or_course_user(current_course, current_course_user)
 json.userName current_user&.name
+json.userId current_user&.id
 
 if current_course_user.present? && can?(:read, current_course)
   json.courseUserName current_course_user.name