Feature: Add transaction multi-select for batch AI review

Add selection UI to Transactions page:
- Add checkbox column for selecting transactions
- Add sticky selection bar showing selected count
- Add Select All / Clear Selection controls
- Wire up form to send selected IDs to AICategorizePreview page
- Preserve row click navigation for unselected areas

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

MoneyMap/Pages/Transactions.cshtml

@@ -133,27 +133,53 @@
     </div>
 }
 
+<!-- Selection Action Bar (hidden by default) -->
+<div id="selectionBar" class="alert alert-primary d-none sticky-top" style="top: 10px; z-index: 1020;">
+    <div class="d-flex justify-content-between align-items-center">
+        <div>
+            <strong><span id="selectedCount">0</span> transaction(s) selected</strong>
+        </div>
+        <div class="d-flex gap-2">
+            <button type="button" class="btn btn-sm btn-outline-primary" onclick="selectAllVisible()">Select All Visible</button>
+            <button type="button" class="btn btn-sm btn-outline-secondary" onclick="clearSelection()">Clear Selection</button>
+            <form id="aiReviewForm" method="post" asp-page="/AICategorizePreview" asp-page-handler="StoreIds" class="d-inline">
+                @Html.AntiForgeryToken()
+                <button type="submit" class="btn btn-sm btn-success">
+                    AI Review Categories
+                </button>
+            </form>
+        </div>
+    </div>
+</div>
+
 <!-- Transactions Table -->
 @if (Model.Transactions.Any())
 {
     <div class="card shadow-sm">
-        <div class="card-header">
+        <div class="card-header d-flex justify-content-between align-items-center">
-            @if (!string.IsNullOrWhiteSpace(Model.Category))
+            <div>
-            {
+                @if (!string.IsNullOrWhiteSpace(Model.Category))
-                <strong>@Model.Category</strong>
+                {
-                <span class="text-muted">- @Model.Stats.Count transactions</span>
+                    <strong>@Model.Category</strong>
-            }
+                    <span class="text-muted">- @Model.Stats.Count transactions</span>
-            else
+                }
-            {
+                else
-                <strong>All Transactions</strong>
+                {
-                <span class="text-muted">- @Model.Stats.Count total</span>
+                    <strong>All Transactions</strong>
-            }
+                    <span class="text-muted">- @Model.Stats.Count total</span>
+                }
+            </div>
+            <div class="form-check">
+                <input type="checkbox" class="form-check-input" id="selectAllCheckbox" onchange="toggleSelectAll(this.checked)">
+                <label class="form-check-label small" for="selectAllCheckbox">Select all on page</label>
+            </div>
         </div>
         <div class="card-body p-0">
             <div class="table-responsive">
                 <table class="table table-hover table-sm mb-0">
                     <thead>
                         <tr>
+                            <th style="width: 40px;"></th>
                             <th style="width: 70px;">ID</th>
                             <th style="width: 110px;">Date</th>
                             <th>Name</th>
@@ -166,12 +192,16 @@
                     <tbody>
                         @foreach (var t in Model.Transactions)
                         {
-                            <tr style="cursor: pointer;" title="Open details" onclick="window.location.href='@Url.Page("/EditTransaction", new { id = t.Id })'">
+                            <tr>
-                                <td class="small text-muted">#@t.Id</td>
+                                <td onclick="event.stopPropagation();">
-                                <td>@t.Date.ToString("yyyy-MM-dd")</td>
+                                    <input type="checkbox" class="form-check-input txn-checkbox"
-                                <td>
+                                           value="@t.Id" onchange="updateSelection()">
+                                </td>
+                                <td class="small text-muted" style="cursor: pointer;" onclick="window.location.href='@Url.Page("/EditTransaction", new { id = t.Id })'">#@t.Id</td>
+                                <td style="cursor: pointer;" onclick="window.location.href='@Url.Page("/EditTransaction", new { id = t.Id })'">@t.Date.ToString("yyyy-MM-dd")</td>
+                                <td style="cursor: pointer;" onclick="window.location.href='@Url.Page("/EditTransaction", new { id = t.Id })'">
                                     <div class="d-flex align-items-center gap-2">
-                                        <a asp-page="/EditTransaction" asp-route-id="@t.Id" class="text-decoration-none text-body">@t.Name</a>
+                                        <span class="text-body">@t.Name</span>
                                         @if (t.ReceiptCount > 0)
                                         {
                                             <span class="badge bg-success" title="@t.ReceiptCount receipt(s) attached">
@@ -187,11 +217,11 @@
                                         }
                                     </div>
                                 </td>
-                                <td class="text-truncate" style="max-width:320px">@t.Memo</td>
+                                <td class="text-truncate" style="max-width:320px; cursor: pointer;" onclick="window.location.href='@Url.Page("/EditTransaction", new { id = t.Id })'">@t.Memo</td>
-                                <td class="text-end @(t.Amount >= 0 ? "text-success" : "")">
+                                <td class="text-end @(t.Amount >= 0 ? "text-success" : "")" style="cursor: pointer;" onclick="window.location.href='@Url.Page("/EditTransaction", new { id = t.Id })'">
                                     @t.Amount.ToString("C")
                                 </td>
-                                <td>
+                                <td style="cursor: pointer;" onclick="window.location.href='@Url.Page("/EditTransaction", new { id = t.Id })'">
                                     @if (string.IsNullOrWhiteSpace(t.Category))
                                     {
                                         <span class="text-muted">(uncategorized)</span>
@@ -201,10 +231,9 @@
                                         @t.Category
                                     }
                                 </td>
-                                <td class="small">
+                                <td class="small" style="cursor: pointer;" onclick="window.location.href='@Url.Page("/EditTransaction", new { id = t.Id })'">
                                     @t.CardLabel
                                 </td>
-                                
                             </tr>
                         }
                     </tbody>
@@ -340,6 +369,56 @@ else
           });
         }
       })();
+
+      // Transaction selection handling
+      function updateSelection() {
+          const checkboxes = document.querySelectorAll('.txn-checkbox:checked');
+          const count = checkboxes.length;
+          const selectionBar = document.getElementById('selectionBar');
+          const selectedCount = document.getElementById('selectedCount');
+          const form = document.getElementById('aiReviewForm');
+
+          selectedCount.textContent = count;
+
+          if (count > 0) {
+              selectionBar.classList.remove('d-none');
+              // Update form with selected IDs
+              const existingInputs = form.querySelectorAll('input[name="transactionIds"]');
+              existingInputs.forEach(input => input.remove());
+
+              checkboxes.forEach(cb => {
+                  const input = document.createElement('input');
+                  input.type = 'hidden';
+                  input.name = 'transactionIds';
+                  input.value = cb.value;
+                  form.appendChild(input);
+              });
+          } else {
+              selectionBar.classList.add('d-none');
+          }
+
+          // Update select all checkbox state
+          const allCheckboxes = document.querySelectorAll('.txn-checkbox');
+          const selectAllCheckbox = document.getElementById('selectAllCheckbox');
+          selectAllCheckbox.checked = allCheckboxes.length > 0 && checkboxes.length === allCheckboxes.length;
+          selectAllCheckbox.indeterminate = checkboxes.length > 0 && checkboxes.length < allCheckboxes.length;
+      }
+
+      function toggleSelectAll(checked) {
+          document.querySelectorAll('.txn-checkbox').forEach(cb => cb.checked = checked);
+          updateSelection();
+      }
+
+      function selectAllVisible() {
+          document.querySelectorAll('.txn-checkbox').forEach(cb => cb.checked = true);
+          updateSelection();
+      }
+
+      function clearSelection() {
+          document.querySelectorAll('.txn-checkbox').forEach(cb => cb.checked = false);
+          document.getElementById('selectAllCheckbox').checked = false;
+          updateSelection();
+      }
     </script>
 }