Merge fx-5-scan-ingestion

The marking flow read student_submissions but there was no way to create them —
print→scan→mark could not be completed in-app. Add an "Upload scans" control to
the marking queue that posts PDFs to the existing POST /batches/{id}/scans and
refreshes the queue.

- examRepository.uploadScan(batchId, file, {studentId?, matchingMethod?}): multipart
  upload (axios sets the boundary), returns the created/updated StudentSubmission.
- ExamMarkingPage: "Upload scans" button + hidden multi-file PDF input; uploads each
  with matching_method='ordered' (fills the roster in order; unmatched scans become
  reconcilable submissions), then reloads the queue with a success/failure summary.

No API or schema change (endpoint already existed). tsc clean; behaviour is covered
by the cc-browser-tester card (FX-V).

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/pages/exam/ExamMarkingPage.tsx

@@ -1,4 +1,4 @@
-import React, { useCallback, useEffect, useMemo, useState } from 'react';
+import React, { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import { useNavigate, useParams } from 'react-router-dom';
 import { v5 as uuidv5 } from 'uuid';
 import {
@@ -21,6 +21,7 @@ import {
 import ArrowBackIcon from '@mui/icons-material/ArrowBack';
 import SaveIcon from '@mui/icons-material/Save';
 import TableChartIcon from '@mui/icons-material/TableChart';
+import UploadFileIcon from '@mui/icons-material/UploadFile';
 
 import { examRepository } from '../../services/exam/examRepository';
 import type { BatchQueueResponse, ExamQuestion, ExamTemplateDetail, StudentSubmission } from '../../types/exam.types';
@@ -43,6 +44,8 @@ const ExamMarkingPage: React.FC = () => {
   const [saving, setSaving] = useState(false);
   const [message, setMessage] = useState<string | null>(null);
   const [error, setError] = useState<string | null>(null);
+  const [uploading, setUploading] = useState(false);
+  const fileInputRef = useRef<HTMLInputElement | null>(null);
 
   const load = useCallback(async () => {
     if (!batchId) return;
@@ -68,6 +71,28 @@ const ExamMarkingPage: React.FC = () => {
     () => (template?.questions ?? []).filter((q) => !q.is_container).sort((a, b) => a.order - b.order),
     [template],
   );
+  const onScanFiles = useCallback(async (files: FileList | null) => {
+    if (!batchId || !files || files.length === 0) return;
+    setUploading(true); setError(null); setMessage(null);
+    let ok = 0;
+    const failures: string[] = [];
+    for (const file of Array.from(files)) {
+      try {
+        // 'ordered' assigns each scan to the next not-yet-submitted roster slot; unmatched scans
+        // become an unmatched submission the teacher can reconcile.
+        await examRepository.uploadScan(batchId, file, { matchingMethod: 'ordered' });
+        ok += 1;
+      } catch (e) {
+        failures.push(`${file.name}: ${e instanceof Error ? e.message : String(e)}`);
+      }
+    }
+    setUploading(false);
+    if (fileInputRef.current) fileInputRef.current.value = '';
+    await load();
+    if (ok) setMessage(`Uploaded ${ok} scan${ok === 1 ? '' : 's'}${failures.length ? `, ${failures.length} failed` : ''}`);
+    if (failures.length) setError(failures.join(' · '));
+  }, [batchId, load]);
+
   const selected = queue?.submissions.find((s) => s.id === selectedId) ?? null;
 
   const saveSelected = async () => {
@@ -154,7 +179,29 @@ const ExamMarkingPage: React.FC = () => {
         <Stack direction={{ xs: 'column', md: 'row' }} spacing={2} alignItems="stretch">
           <Card variant="outlined" sx={{ width: { xs: '100%', md: 340 }, flexShrink: 0 }}>
             <CardContent>
-              <Typography variant="h6" gutterBottom>Marking queue</Typography>
+              <Box sx={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', gap: 1, mb: 1 }}>
+                <Typography variant="h6">Marking queue</Typography>
+                <Button
+                  size="small"
+                  variant="outlined"
+                  startIcon={<UploadFileIcon fontSize="small" />}
+                  disabled={uploading}
+                  onClick={() => fileInputRef.current?.click()}
+                >
+                  {uploading ? 'Uploading…' : 'Upload scans'}
+                </Button>
+                <input
+                  ref={fileInputRef}
+                  type="file"
+                  accept="application/pdf"
+                  multiple
+                  hidden
+                  onChange={(e) => { void onScanFiles(e.target.files); }}
+                />
+              </Box>
+              <Typography variant="caption" color="text.secondary" sx={{ display: 'block', mb: 1 }}>
+                Scanned PDFs fill the roster in order; unmatched scans appear below to reconcile.
+              </Typography>
               <Stack direction="row" spacing={1} sx={{ mb: 1 }} flexWrap="wrap" useFlexGap>
                 <Chip size="small" label={`${queue?.progress.total ?? 0} total`} />
                 <Chip size="small" label={`${queue?.progress.absent ?? 0} absent`} color="warning" variant="outlined" />

src/services/exam/examRepository.ts

@@ -28,6 +28,7 @@ import type {
   Neo4jSyncResult,
   PatchQuestionPayload,
   SpecPoint,
+  StudentSubmission,
   TemplateReplacePayload,
   UpdateTemplateMetaPayload,
 } from '../../types/exam.types';
@@ -298,6 +299,21 @@ export const examRepository = {
     const res = await axios.put(`${EXAM_BASE}/marks/${markId}`, payload, { headers });
     return res.data;
   },
+
+  async uploadScan(
+    batchId: string,
+    file: File,
+    opts: { studentId?: string; matchingMethod?: 'manual' | 'ordered' } = {},
+  ): Promise<StudentSubmission> {
+    const headers = await authHeaders();
+    const form = new FormData();
+    form.append('file', file);
+    form.append('matching_method', opts.matchingMethod ?? 'ordered');
+    if (opts.studentId) form.append('student_id', opts.studentId);
+    // Let axios set the multipart Content-Type + boundary (only Authorization is forwarded).
+    const res = await axios.post<StudentSubmission>(`${EXAM_BASE}/batches/${batchId}/scans`, form, { headers });
+    return res.data;
+  },
 };
 
 export default examRepository;

src/utils/exam-canvas/model.test.ts

@@ -92,4 +92,28 @@ describe('exam setup canvas serialization', () => {
     expect(payload.boundaries.find((b) => b.id === '44444444-4444-4444-8444-444444444444')).toMatchObject({ source: 'ai', confirmed: false, confidence: 0.62, derivation: 'g6' })
   })
 
+  it('never drops a response region that has no enclosing part — it falls back to a question', () => {
+    const payload = serializeCanvasShapes(template, [
+      { id: 'b-top', kind: 'boundary', x: 40, y: 100, w: 700, h: 8, label: 'Q1 start' },
+      { id: 'b-bottom', kind: 'boundary', x: 40, y: 700, w: 700, h: 8, label: 'Q1 end' },
+      { id: 'part-1', kind: 'part', x: 100, y: 180, w: 400, h: 120, label: 'Q1(a)', maxMarks: 3 },
+      { id: 'resp-far', kind: 'response', x: 100, y: 520, w: 300, h: 90, responseForm: 'lines' }, // outside the part box
+    ])
+    const part = payload.questions.find((q) => !q.is_container)
+    expect(payload.response_areas).toHaveLength(1)               // previously dropped (no containing part)
+    expect(payload.response_areas[0].question_id).toBe(part?.id) // falls back to the part, not lost
+  })
+
+  it('respects a region persisted question over geometric nearest when no part contains it', () => {
+    const A = '11111111-1111-4111-8111-111111111111'
+    const B = '22222222-2222-4222-8222-222222222222'
+    const R = '33333333-3333-4333-8333-333333333333'
+    const payload = serializeCanvasShapes(template, [
+      { id: 'pa', kind: 'part', x: 100, y: 120, w: 300, h: 80, label: 'A', questionId: A },
+      { id: 'pb', kind: 'part', x: 100, y: 500, w: 300, h: 80, label: 'B', questionId: B },
+      { id: R, kind: 'response', x: 120, y: 260, w: 200, h: 60, questionId: B }, // contained by neither; nearest is A
+    ])
+    expect(payload.response_areas.find((r) => r.id === R)?.question_id).toBe(B) // persisted B wins over nearest A
+  })
+
 })

src/utils/exam-canvas/model.ts

@@ -147,11 +147,22 @@ export function serializeCanvasShapes(template: ExamTemplateDetail, shapes: Exam
     questions.push({ id: qid, parent_id: parentBand?.questionId ?? null, label: part.label || `Part ${index + 1}`, order: index, max_marks: Number(part.maxMarks ?? 0), answer_type: part.answerType ?? 'written', mcq_options: null, mark_scheme: {}, is_container: false, spec_ref: null, bounds: bounds(part), page: pageForShape(part, pages), source: persistedSource(part), confirmed: persistedConfirmed(part), confidence: persistedConfidence(part), derivation: persistedDerivation(part) })
   })
 
+  // Resolve each region's owner question. Order: current geometric containment (a user who drags a
+  // region into a part re-attaches it) → the PERSISTED attachment if it still points at a saved
+  // question (survives pixel-overflow drift and regions with no enclosing part) → nearest part on the
+  // page → first part → first question of any kind. exam_response_areas.question_id is NOT NULL, so we
+  // never silently drop a region while any question exists (only a template with zero questions can).
+  const questionIds = new Set(questions.map((q) => q.id))
   const response_areas: TemplateReplacePayload['response_areas'] = []
   for (const region of regions) {
     const containingPart = parts.find((part) => contains(bounds(part), bounds(region)))
-    const fallbackPart = parts.find((part) => pageForShape(part, pages) === pageForShape(region, pages)) ?? parts[0]
+    const persisted = isUuid(region.questionId) && questionIds.has(region.questionId) ? region.questionId : undefined
-    const questionId = containingPart ? partQuestionIds.get(containingPart.id) : fallbackPart ? partQuestionIds.get(fallbackPart.id) : undefined
+    const nearestPart = parts.find((part) => pageForShape(part, pages) === pageForShape(region, pages)) ?? parts[0]
+    const questionId =
+      (containingPart && partQuestionIds.get(containingPart.id))
+      || persisted
+      || (nearestPart && partQuestionIds.get(nearestPart.id))
+      || questions[0]?.id
     if (!questionId) continue
     const kind = region.kind as ExamCanvasRegionKind
     response_areas.push({ id: isUuid(region.id) ? region.id : newDomainId(), question_id: questionId, page: pageForShape(region, pages), bounds: bounds(region), kind, response_form: kind === 'response' ? (region.responseForm ?? 'lines') : null, context_type: kind === 'context' ? (region.contextType ?? 'generic') : null, source: persistedSource(region), confirmed: persistedConfirmed(region), confidence: persistedConfidence(region), mark_subtype: null, derivation: persistedDerivation(region) })