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/locales/en.json

@@ -260,6 +260,11 @@
   "postprocessing.error.required": "Please fill in all required fields",
   "postprocessing.error.delete": "Failed to delete processing template",
   "postprocessing.config.show": "Show settings",
+  "postprocessing.test.title": "Test Processing Template",
+  "postprocessing.test.source_stream": "Source Stream:",
+  "postprocessing.test.running": "Testing processing template...",
+  "postprocessing.test.error.no_stream": "Please select a source stream",
+  "postprocessing.test.error.failed": "Processing template test failed",
   "device.button.stream_selector": "Stream Settings",
   "device.stream_settings.title": "📺 Stream Settings",
   "device.stream_selector.label": "Picture Stream:",

server/src/wled_controller/static/locales/ru.json

@@ -260,6 +260,11 @@
   "postprocessing.error.required": "Пожалуйста, заполните все обязательные поля",
   "postprocessing.error.delete": "Не удалось удалить шаблон обработки",
   "postprocessing.config.show": "Показать настройки",
+  "postprocessing.test.title": "Тест шаблона обработки",
+  "postprocessing.test.source_stream": "Источник потока:",
+  "postprocessing.test.running": "Тестирование шаблона обработки...",
+  "postprocessing.test.error.no_stream": "Пожалуйста, выберите источник потока",
+  "postprocessing.test.error.failed": "Тест шаблона обработки не удался",
   "device.button.stream_selector": "Настройки потока",
   "device.stream_settings.title": "📺 Настройки потока",
   "device.stream_selector.label": "Видеопоток:",