Improve device cards, stream/template UI, and add PP template testing

- Move WLED UI button into URL badge as clickable link on device cards
- Remove version label from device cards
- Show PP template name on processed stream cards
- Display filter chain as pills on processing template cards
- Add processing template test with source stream selector
- Pre-load PP templates when viewing streams to fix race condition
- Add ESC key handling for all modals
- Add filter chain CSS styles

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/static/index.html

@@ -490,6 +490,34 @@
         </div>
     </div>
 
+    <!-- Test PP Template Modal -->
+    <div id="test-pp-template-modal" class="modal">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h2 data-i18n="postprocessing.test.title">Test Processing Template</h2>
+                <button class="modal-close-btn" onclick="closeTestPPTemplateModal()" title="Close">&#x2715;</button>
+            </div>
+            <div class="modal-body">
+                <div class="form-group">
+                    <label data-i18n="postprocessing.test.source_stream">Source Stream:</label>
+                    <select id="test-pp-source-stream"></select>
+                </div>
+                <div class="form-group">
+                    <label for="test-pp-duration">
+                        <span data-i18n="streams.test.duration">Capture Duration (s):</span>
+                        <span id="test-pp-duration-value">5</span>
+                    </label>
+                    <input type="range" id="test-pp-duration" min="1" max="10" step="1" value="5" oninput="updatePPTestDuration(this.value)" />
+                </div>
+
+                <button type="button" class="btn btn-primary" onclick="runPPTemplateTest()" style="margin-top: 16px;">
+                    <span data-i18n="streams.test.run">🧪 Run Test</span>
+                </button>
+
+            </div>
+        </div>
+    </div>
+
     <!-- Picture Stream Modal -->
     <div id="stream-modal" class="modal">
         <div class="modal-content">