fix: one label for picking a session back up

Start for an unsat session and Resume for a started one is a distinction
the learner does not have to make. The session exists the moment it is
created, so picking it up is resuming it whether or not a question has
been answered yet.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TqXevQJhxFrM7jJg82cgZN

frontend/src/pages/AnalysisSessionPage.jsx

@@ -199,8 +199,11 @@ export default function AnalysisSessionPage() {
                 decision as far as possible from the result it follows from. */}
             <div className="an-actions">
               {data.not_started ? (
+                // One label either way. The session exists the moment it is
+                // made, so picking it up is resuming it whether or not a
+                // question has been answered yet.
                 <Link className="btn btn-primary" to={`/study/${data.quiz_id}?start=1`}>
-                  Start session
+                  Resume session
                 </Link>
               ) : (
                 <>

frontend/src/pages/AnalysisSessionPage.test.jsx

@@ -72,7 +72,7 @@ describe('a session nobody has sat', () => {
 
   it('offers the sitting, and nothing that makes no sense yet', async () => {
     mountQuiz()
-    expect(await screen.findByRole('link', { name: 'Start session' }))
+    expect(await screen.findByRole('link', { name: 'Resume session' }))
       .toHaveAttribute('href', '/study/3?start=1')
     expect(screen.queryByRole('link', { name: 'Review answers' })).not.toBeInTheDocument()
     expect(screen.queryByRole('button', { name: 'Delete session' })).not.toBeInTheDocument()