Add CSPT entity, processed CSS source type, reverse filter, and UI improvements

- Add Color Strip Processing Template (CSPT) entity: reusable filter chains
  for 1D LED strip postprocessing (backend, storage, API, frontend CRUD)
- Add "processed" color strip source type that wraps another CSS source and
  applies a CSPT filter chain (dataclass, stream, schema, modal, cards)
- Add Reverse filter for strip LED order reversal
- Add CSPT and processed CSS nodes/edges to visual graph editor
- Add CSPT test preview WS endpoint with input source selection
- Add device settings CSPT template selector (add + edit modals with hints)
- Use icon grids for palette quantization preset selector in filter lists
- Use EntitySelect for template references and test modal source selectors
- Fix filters.css_filter_template.desc missing localization
- Fix icon grid cell height inequality (grid-auto-rows: 1fr)
- Rename "Processed" subtab to "Processing Templates"
- Localize all new strings (en/ru/zh)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/wled_controller/static/js/features/graph-editor.js

@@ -11,7 +11,7 @@ import {
     streamsCache, audioSourcesCache, audioTemplatesCache,
     valueSourcesCache, colorStripSourcesCache, syncClocksCache,
     outputTargetsCache, patternTemplatesCache, scenePresetsCache,
-    automationsCacheObj,
+    automationsCacheObj, csptCache,
 } from '../core/state.js';
 import { fetchWithAuth } from '../core/api.js';
 import { showToast, showConfirm } from '../core/ui.js';
@@ -515,13 +515,13 @@ async function _fetchAllEntities() {
         devices, captureTemplates, ppTemplates, pictureSources,
         audioSources, audioTemplates, valueSources, colorStripSources,
         syncClocks, outputTargets, patternTemplates, scenePresets, automations,
-        batchStatesResp,
+        csptTemplates, batchStatesResp,
     ] = await Promise.all([
         devicesCache.fetch(), captureTemplatesCache.fetch(), ppTemplatesCache.fetch(),
         streamsCache.fetch(), audioSourcesCache.fetch(), audioTemplatesCache.fetch(),
         valueSourcesCache.fetch(), colorStripSourcesCache.fetch(), syncClocksCache.fetch(),
         outputTargetsCache.fetch(), patternTemplatesCache.fetch(), scenePresetsCache.fetch(),
-        automationsCacheObj.fetch(),
+        automationsCacheObj.fetch(), csptCache.fetch(),
         fetchWithAuth('/output-targets/batch/states').catch(() => null),
     ]);
 
@@ -540,6 +540,7 @@ async function _fetchAllEntities() {
         devices, captureTemplates, ppTemplates, pictureSources,
         audioSources, audioTemplates, valueSources, colorStripSources,
         syncClocks, outputTargets: enrichedTargets, patternTemplates, scenePresets, automations,
+        csptTemplates,
     };
 }