Feature: Add category pie chart and case-insensitive search

- Add doughnut chart showing spending by category
- Fix search to use EF.Functions.Like for explicit case-insensitivity
- Include Chart.js CDN for chart rendering

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

MoneyMap/Pages/Transactions.cshtml

@@ -122,6 +122,17 @@
     </div>
 </div>
 
+<!-- Pie Chart -->
+@if (Model.CategoryBreakdowns.Any())
+{
+    <div class="card shadow-sm mb-3">
+        <div class="card-header">Spending by category</div>
+        <div class="card-body">
+            <canvas id="categoryChart" height="220"></canvas>
+        </div>
+    </div>
+}
+
 <!-- Transactions Table -->
 @if (Model.Transactions.Any())
 {
@@ -304,6 +315,31 @@ else
 }
 
 @section Scripts {
+    <script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
     <script src="~/js/transactions.js"></script>
+    <script>
+      (function(){
+        const categoryLabels = @Html.Raw(System.Text.Json.JsonSerializer.Serialize(Model.CategoryBreakdowns.Select(c => string.IsNullOrWhiteSpace(c.Category) ? "(uncategorized)" : c.Category)));
+        const categoryValues = @Html.Raw(System.Text.Json.JsonSerializer.Serialize(Model.CategoryBreakdowns.Select(c => c.TotalSpend)));
+
+        const catCtx = document.getElementById('categoryChart');
+        if (catCtx && categoryLabels.length) {
+          new Chart(catCtx, {
+            type: 'doughnut',
+            data: {
+              labels: categoryLabels,
+              datasets: [{
+                data: categoryValues,
+                backgroundColor: ['#4e79a7','#f28e2c','#e15759','#76b7b2','#59a14f','#edc948','#b07aa1','#ff9da7','#9c755f','#bab0ab']
+              }]
+            },
+            options: {
+              plugins: { legend: { position: 'bottom' } },
+              maintainAspectRatio: false
+            }
+          });
+        }
+      })();
+    </script>
 }
 

MoneyMap/Pages/Transactions.cshtml.cs

@@ -50,6 +50,7 @@ namespace MoneyMap.Pages
         public List<string> AvailableMerchants { get; set; } = new();
         public List<Card> AvailableCards { get; set; } = new();
         public TransactionStats Stats { get; set; } = new();
+        public List<CategoryBreakdown> CategoryBreakdowns { get; set; } = new();
 
         public async Task OnGetAsync()
         {
@@ -61,15 +62,16 @@ namespace MoneyMap.Pages
                 .Include(t => t.Merchant)
                 .AsQueryable();
 
-            // Apply filters
+            // Apply filters (case-insensitive search using EF.Functions.Like)
             if (!string.IsNullOrWhiteSpace(Search))
             {
+                var searchPattern = $"%{Search}%";
                 query = query.Where(t =>
-                    t.Name.Contains(Search) ||
-                    (t.Memo != null && t.Memo.Contains(Search)) ||
-                    (t.Category != null && t.Category.Contains(Search)) ||
-                    (t.Notes != null && t.Notes.Contains(Search)) ||
-                    (t.Merchant != null && t.Merchant.Name.Contains(Search)));
+                    EF.Functions.Like(t.Name, searchPattern) ||
+                    (t.Memo != null && EF.Functions.Like(t.Memo, searchPattern)) ||
+                    (t.Category != null && EF.Functions.Like(t.Category, searchPattern)) ||
+                    (t.Notes != null && EF.Functions.Like(t.Notes, searchPattern)) ||
+                    (t.Merchant != null && EF.Functions.Like(t.Merchant.Name, searchPattern)));
             }
 
             if (!string.IsNullOrWhiteSpace(Category))
@@ -154,6 +156,21 @@ namespace MoneyMap.Pages
             // Calculate stats for filtered results (all pages, not just current)
             Stats = await _statsService.CalculateStatsAsync(query);
 
+            // Calculate category breakdown for pie chart (only expenses)
+            var expenseQuery = query.Where(t => t.Amount < 0).ExcludeTransfers();
+            var categoryGroups = await expenseQuery
+                .GroupBy(t => t.Category ?? "")
+                .Select(g => new CategoryBreakdown
+                {
+                    Category = g.Key,
+                    TotalSpend = g.Sum(x => -x.Amount),
+                    Count = g.Count()
+                })
+                .OrderByDescending(x => x.TotalSpend)
+                .ToListAsync();
+
+            CategoryBreakdowns = categoryGroups;
+
             // Get available categories for filter dropdown
             AvailableCategories = await _referenceDataService.GetAvailableCategoriesAsync();
 
@@ -178,5 +195,12 @@ namespace MoneyMap.Pages
             public string AccountLabel { get; set; } = "";
             public int ReceiptCount { get; set; }
         }
+
+        public class CategoryBreakdown
+        {
+            public string Category { get; set; } = "";
+            public decimal TotalSpend { get; set; }
+            public int Count { get; set; }
+        }
     }
 }