fix: match filenames against both animal_id_string and animal_name

Multi-word names ("Rat A") now allow any word separator in the
filename — space, underscore, or dash — so "Rat_A_session.csv"
and "Rat-A-data.bin" both match. Single-word names and numeric IDs
are unchanged. Partial overlaps still rejected ("Rat" won't hit
"Rationale"). Tests: 5 new name-based match cases (24 total).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/FileDropZone.jsx

@@ -9,15 +9,29 @@ function escapeRegex(str) {
 
 /**
  * Build a regex that matches an animal's identifier in a filename.
- * Matches only when the ID is not surrounded by other alphanumeric chars,
+ * Tries both animal_id_string and animal_name (OR logic).
+ *
+ * Rules:
+ *  - Match must not be preceded or followed by an alphanumeric char,
  *    so "2852" matches "rat_2852_session" but not "28520" or "X2852Y".
+ *  - Multi-word names ("Rat A") allow any separator (space, dash, underscore)
+ *    between words, so "Rat A" matches "rat_a_session" and "Rat-A-data".
  */
 function buildAnimalRegex(animal) {
-  const ids = [];
-  if (animal.animal_id_string) ids.push(escapeRegex(animal.animal_id_string));
-  if (animal.animal_name)      ids.push(escapeRegex(animal.animal_name));
-  if (ids.length === 0) return null;
-  return new RegExp(`(?<![a-zA-Z0-9])(${ids.join('|')})(?![a-zA-Z0-9])`, 'i');
+  const patterns = [];
+
+  if (animal.animal_id_string) {
+    patterns.push(escapeRegex(animal.animal_id_string));
+  }
+
+  if (animal.animal_name) {
+    const words = animal.animal_name.trim().split(/\s+/).map(escapeRegex);
+    // Single-word name: use as-is. Multi-word: allow space/dash/underscore between words.
+    patterns.push(words.length === 1 ? words[0] : words.join('[\\s_\\-]+'));
+  }
+
+  if (patterns.length === 0) return null;
+  return new RegExp(`(?<![a-zA-Z0-9])(${patterns.join('|')})(?![a-zA-Z0-9])`, 'i');
 }
 
 function classifyFile(filename) {

frontend/tests/FileDropZone.test.jsx

@@ -142,6 +142,55 @@ describe('filename-to-subject matching', () => {
     expect(screen.getByText(/unmatched/i)).toBeInTheDocument();
   });
 
+  // ── animal_name matching ───────────────────────────────────────────────────
+
+  it('matches by animal_name when the name appears literally in the filename', async () => {
+    const animal = { id: 'b1', animal_name: 'Homer', animal_id_string: null };
+    const row    = { animal, status: { id: 's-b1', animal_id: 'b1', date: `${DATE}T00:00:00.000Z` } };
+    render(<FileDropZone rows={[row]} date={DATE} />);
+    dropFiles([makeFile(`${DATE}_Homer_session.csv`)]);
+    await waitFor(() => screen.getByTestId('drop-preview'));
+    expect(screen.queryByText(/unmatched/i)).not.toBeInTheDocument();
+    expect(screen.getByText(`${DATE}_Homer_session.csv`)).toBeInTheDocument();
+  });
+
+  it('matches multi-word animal_name with underscores as separator in filename', async () => {
+    const animal = { id: 'b1', animal_name: 'Rat A', animal_id_string: null };
+    const row    = { animal, status: { id: 's-b1', animal_id: 'b1', date: `${DATE}T00:00:00.000Z` } };
+    render(<FileDropZone rows={[row]} date={DATE} />);
+    dropFiles([makeFile(`${DATE}_Rat_A_trials.csv`)]);
+    await waitFor(() => screen.getByTestId('drop-preview'));
+    expect(screen.queryByText(/unmatched/i)).not.toBeInTheDocument();
+  });
+
+  it('matches multi-word animal_name with dashes as separator in filename', async () => {
+    const animal = { id: 'b1', animal_name: 'Rat A', animal_id_string: null };
+    const row    = { animal, status: { id: 's-b1', animal_id: 'b1', date: `${DATE}T00:00:00.000Z` } };
+    render(<FileDropZone rows={[row]} date={DATE} />);
+    dropFiles([makeFile(`${DATE}-Rat-A-session.bin`)]);
+    await waitFor(() => screen.getByTestId('drop-preview'));
+    expect(screen.queryByText(/unmatched/i)).not.toBeInTheDocument();
+  });
+
+  it('matches by animal_name even when animal_id_string is also set (OR logic)', async () => {
+    const animal = { id: 'b1', animal_name: 'Rat A', animal_id_string: '2852' };
+    const row    = { animal, status: { id: 's-b1', animal_id: 'b1', date: `${DATE}T00:00:00.000Z` } };
+    render(<FileDropZone rows={[row]} date={DATE} />);
+    // File uses name, not ID
+    dropFiles([makeFile(`${DATE}_Rat_A_ephys.bin`)]);
+    await waitFor(() => screen.getByTestId('drop-preview'));
+    expect(screen.queryByText(/unmatched/i)).not.toBeInTheDocument();
+  });
+
+  it('does not match a partial name overlap (Rat should not match Rationale)', async () => {
+    const animal = { id: 'b1', animal_name: 'Rat', animal_id_string: null };
+    const row    = { animal, status: { id: 's-b1', animal_id: 'b1', date: `${DATE}T00:00:00.000Z` } };
+    render(<FileDropZone rows={[row]} date={DATE} />);
+    dropFiles([makeFile('Rationale_study_data.csv')]);
+    await waitFor(() => screen.getByTestId('drop-preview'));
+    expect(screen.getByText(/unmatched/i)).toBeInTheDocument();
+  });
+
   it('shows warning for subjects with no matched files', async () => {
     render(<FileDropZone rows={ROWS} date={DATE} />);
     // Only drop file for 2852 — 3076 and 3077 get no match