feat(admin): add mapping workflow for unknown CSVs

- New POST /admin/map-files to reclassify unknown files to a chosen import type
- Centralize VALID_IMPORT_TYPES and pass to admin template
- UI: dropdown + 'Map Selected' button in Unknown card
- JS: mapSelectedFiles() posts selection and reloads on success
- Keeps UUID suffix, prevents traversal, logs actions

app/templates/admin.html

@@ -463,6 +463,21 @@
                                     </h6>
                                 </div>
                                 <div class="card-body">
+                                    {% if import_type == 'unknown' and valid_import_types %}
+                                    <div class="mb-3 d-flex align-items-end gap-2">
+                                        <div>
+                                            <label class="form-label mb-1">Map selected to:</label>
+                                            <select class="form-select form-select-sm" id="mapTypeSelect-{{ loop.index }}">
+                                                {% for t in valid_import_types %}
+                                                <option value="{{ t }}">{{ t.title().replace('_', ' ') }}</option>
+                                                {% endfor %}
+                                            </select>
+                                        </div>
+                                        <button type="button" class="btn btn-sm btn-warning" onclick="mapSelectedFiles(this, '{{ import_type }}')">
+                                            <i class="bi bi-tags"></i> Map Selected
+                                        </button>
+                                    </div>
+                                    {% endif %}
                                     <form action="/admin/import/{{ import_type }}" method="post">
                                         <div class="mb-3">
                                             <div class="d-flex justify-content-between align-items-center mb-2">
@@ -783,5 +798,48 @@ async function deleteFile(filename, event) {
         alert(`Error deleting file: ${error.message}`);
     }
 }
+
+// Map selected unknown files to a chosen import type
+async function mapSelectedFiles(buttonEl, importType) {
+    // Find the surrounding card and form
+    const cardBody = buttonEl.closest('.card-body');
+    const form = cardBody.querySelector('form');
+    const selectEl = cardBody.querySelector('select.form-select');
+    if (!form || !selectEl) return;
+
+    // Collect selected filenames
+    const checked = Array.from(form.querySelectorAll('.file-checkbox:checked'))
+        .map(cb => cb.value);
+    if (checked.length === 0) {
+        alert('Select at least one file to map.');
+        return;
+    }
+
+    const targetType = selectEl.value;
+    if (!targetType) {
+        alert('Choose a target type.');
+        return;
+    }
+
+    buttonEl.disabled = true;
+    try {
+        const resp = await fetch('/admin/map-files', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({ target_type: targetType, filenames: checked })
+        });
+        if (!resp.ok) {
+            const err = await resp.json().catch(() => ({}));
+            throw new Error(err.detail || 'Mapping failed');
+        }
+        // Refresh UI
+        window.location.reload();
+    } catch (e) {
+        console.error(e);
+        alert(`Mapping failed: ${e.message}`);
+    } finally {
+        buttonEl.disabled = false;
+    }
+}
 </script>
 {% endblock %}