Update README and help pages

BudgetApp/Components/Pages/Help.razor

@@ -125,6 +125,32 @@
             </div>
         </div>
 
+        @* ── Reports ── *@
+        <div class="card mb-4" id="reports">
+            <div class="card-header">
+                <h5 class="mb-0">📈 Reports</h5>
+            </div>
+            <div class="card-body">
+                <p>The <a href="/reports">Reports</a> page gives you a visual breakdown of your spending and income over a chosen time period.</p>
+
+                <h6>Filters</h6>
+                <ul>
+                    <li>Use the preset buttons (<strong>7d</strong>, <strong>30d</strong>, <strong>90d</strong>, <strong>1y</strong>) or pick custom start/end dates to set the time range.</li>
+                    <li>Toggle individual accounts on or off to include or exclude them from the charts and summary.</li>
+                </ul>
+
+                <h6>Charts</h6>
+                <ul>
+                    <li><strong>Expenses by Category</strong> — a doughnut chart showing how your spending is distributed across categories.</li>
+                    <li><strong>Income by Category</strong> — a doughnut chart showing the sources of your income.</li>
+                    <li><strong>Monthly Income vs Expenses</strong> — a bar chart comparing total income and expenses for each month in the selected range.</li>
+                </ul>
+
+                <h6>Category Summary Table</h6>
+                <p class="mb-0">Below the charts is a table listing every category with its total income, total expenses and net amount. A totals row at the bottom shows the overall figures for the period.</p>
+            </div>
+        </div>
+
         @* ── Settings ── *@
         <div class="card mb-4" id="settings">
             <div class="card-header">
@@ -168,6 +194,7 @@
                 <a href="/help#accounts" class="list-group-item list-group-item-action">🏦 Accounts</a>
                 <a href="/help#transactions" class="list-group-item list-group-item-action">💸 Transactions</a>
                 <a href="/help#categories" class="list-group-item list-group-item-action">🏷️ Categories</a>
+                <a href="/help#reports" class="list-group-item list-group-item-action">📈 Reports</a>
                 <a href="/help#settings" class="list-group-item list-group-item-action">⚙️ Settings</a>
                 <a href="/help#tips" class="list-group-item list-group-item-action">💡 Tips</a>
             </div>