Add backdrop click to Add/Edit Template modal, document dialog UI standards

- Add backdrop click handlers to showAddTemplateModal() and editTemplate() to close modal when clicking outside
- Create new "Frontend UI Patterns" section in CLAUDE.md documenting modal dialog standards
- Document backdrop click behavior with code example
- Document close button requirements for dialogs with Cancel buttons

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

server/CLAUDE.md

@@ -6,6 +6,8 @@
 
 **IMPORTANT**: When making changes to server code (Python files in `src/wled_controller/`), you MUST restart the server if it's currently running to ensure the changes take effect.
 
+**NOTE**: Auto-reload is currently disabled (`reload=False` in `main.py`) due to watchfiles causing an infinite reload loop. Changes to server code will NOT be automatically picked up - manual server restart is required.
+
 #### When to restart:
 - After modifying API routes (`api/routes.py`, `api/schemas.py`)
 - After updating core logic (`core/*.py`)
@@ -102,6 +104,56 @@ After restarting the server with new code:
 3. Use `t('key')` function in `static/app.js` for dynamic content
 4. No server restart needed (frontend only)
 
+## Frontend UI Patterns
+
+### Modal Dialogs
+
+**IMPORTANT**: All modal dialogs must follow these standards for consistent UX:
+
+#### Backdrop Click Behavior
+All modals MUST close when the user clicks outside the dialog (on the backdrop). Implement this by adding a click handler that checks if the clicked element is the modal backdrop itself:
+
+```javascript
+// Show modal
+const modal = document.getElementById('my-modal');
+modal.style.display = 'flex';
+
+// Add backdrop click handler to close modal
+modal.onclick = function(event) {
+    if (event.target === modal) {
+        closeMyModal();
+    }
+};
+```
+
+**Where to add**: In every function that shows a modal (e.g., `showAddTemplateModal()`, `editTemplate()`, `showTestTemplateModal()`).
+
+#### Close Button Requirement
+Each modal dialog that has a "Cancel" button MUST also have a cross (×) close button at the top-right corner of the dialog. This provides users with multiple intuitive ways to dismiss the dialog:
+
+1. Click the backdrop (outside the dialog)
+2. Click the × button (top-right corner)
+3. Click the Cancel button (bottom of dialog)
+4. Press Escape key (if implemented)
+
+**HTML Structure**:
+```html
+<div class="modal-content">
+    <button class="close-btn" onclick="closeMyModal()">&times;</button>
+    <h2>Dialog Title</h2>
+    <!-- dialog content -->
+    <div class="modal-actions">
+        <button onclick="closeMyModal()">Cancel</button>
+        <button onclick="submitAction()">Submit</button>
+    </div>
+</div>
+```
+
+**CSS Requirements**:
+- Close button should be positioned absolutely at top-right
+- Should be easily clickable (min 24px × 24px hit area)
+- Should have clear hover state
+
 ## Authentication
 
 Server uses API key authentication. Keys are configured in:

server/src/wled_controller/static/app.js

@@ -2281,7 +2281,16 @@ async function showAddTemplateModal() {
     // Load available engines
     await loadAvailableEngines();
 
-    document.getElementById('template-modal').style.display = 'flex';
+    // Show modal
+    const modal = document.getElementById('template-modal');
+    modal.style.display = 'flex';
+
+    // Add backdrop click handler to close modal
+    modal.onclick = function(event) {
+        if (event.target === modal) {
+            closeTemplateModal();
+        }
+    };
 }
 
 // Edit template
@@ -2315,7 +2324,16 @@ async function editTemplate(templateId) {
         document.getElementById('template-test-results').style.display = 'none';
         document.getElementById('template-error').style.display = 'none';
 
-        document.getElementById('template-modal').style.display = 'flex';
+        // Show modal
+        const modal = document.getElementById('template-modal');
+        modal.style.display = 'flex';
+
+        // Add backdrop click handler to close modal
+        modal.onclick = function(event) {
+            if (event.target === modal) {
+                closeTemplateModal();
+            }
+        };
     } catch (error) {
         console.error('Error loading template:', error);
         showToast(t('templates.error.load') + ': ' + error.message, 'error');