Fix empty coaches list in workshop feedback form (Issue #2367)

Resolves issue where no coaches appeared in the feedback dropdown when
students tried to submit workshop feedback.

Root cause: The feedback controller was filtering for coaches where
attended=true, but attendance is only marked after organizers manually
verify it. When feedback emails are sent (the day after workshop),
coaches have attending=true but attended=nil.

Changes:
- Updated set_coaches to use accepted_or_attended scope instead of attended
- Added ORDER BY with NULLS LAST to prioritize verified coaches first
- Added test for coaches who RSVPd but haven't been verified yet
- Added test for verified coaches appearing before unverified coaches

This allows students to submit feedback immediately after workshops,
even before organizers verify attendance, while still prioritizing
verified coaches when that data is available.

Fixes #2367

Author: mroderick

app/controllers/feedback_controller.rb

@@ -38,6 +38,8 @@ def feedback_params
   end
 
   def set_coaches(workshop)
-    @coaches = workshop.invitations.to_coaches.attended.map(&:member)
+    @coaches = workshop.invitations.to_coaches.accepted_or_attended
+      .order(Arel.sql('attended DESC NULLS LAST'))
+      .map(&:member)
   end
 end

spec/features/member_feedback_spec.rb

@@ -38,6 +38,51 @@
 
       expect(page).to have_select('feedback_tutorial_id', with_options: [@tutorial.title])
     end
+
+    scenario 'I can see coaches who RSVPd but have not yet been marked as attended (Issue #2367)' do
+      # This reproduces the real-world scenario where:
+      # 1. Coach RSVPs to workshop (attending = true)
+      # 2. Feedback is sent the next day
+      # 3. Organizer hasn't yet marked attendance (attended = nil)
+      coach_not_yet_verified = Fabricate(:coach)
+      Fabricate(:attending_workshop_invitation,
+        workshop: feedback_request.workshop,
+        member: coach_not_yet_verified,
+        role: 'Coach',
+        attended: nil)
+
+      visit feedback_path(valid_token)
+
+      # Coach should appear in the list even though attended is nil
+      expect(page).to have_select('feedback_coach_id', with_options: [coach_not_yet_verified.full_name])
+    end
+
+    scenario 'verified coaches appear before unverified coaches in the list' do
+      # Create two coaches: one verified (attended=true), one not yet (attended=nil)
+      verified_coach = Fabricate(:coach, name: 'Alice', surname: 'Verified')
+      unverified_coach = Fabricate(:coach, name: 'Bob', surname: 'Unverified')
+
+      Fabricate(:attended_workshop_invitation,
+        workshop: feedback_request.workshop,
+        member: verified_coach,
+        role: 'Coach')
+
+      Fabricate(:attending_workshop_invitation,
+        workshop: feedback_request.workshop,
+        member: unverified_coach,
+        role: 'Coach',
+        attended: nil)
+
+      visit feedback_path(valid_token)
+
+      # Get all coach options in order
+      select_options = page.find('#feedback_coach_id').all('option').map(&:text).reject(&:blank?)
+      verified_index = select_options.index(verified_coach.full_name)
+      unverified_index = select_options.index(unverified_coach.full_name)
+
+      # Verified coach should appear before unverified coach
+      expect(verified_index).to be < unverified_index
+    end
   end
 
   context 'I get redirected to the main page' do