Add Chinese locale, fix audio device duplicates, remove display lock restriction

- Add Simplified Chinese (中文) locale with all 906 translation keys
- Fix duplicate audio devices: WASAPI two-pass enumerate avoids double-listing
  loopback endpoints; cross-engine dedup by (name, is_loopback) prefers
  higher-priority engine
- Remove redundant display lock check from capture template, picture source,
  and postprocessing template test endpoints — screen capture is read-only
  and concurrent access is safe

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

server/src/wled_controller/api/routes/postprocessing.py

@@ -11,10 +11,8 @@ from fastapi import APIRouter, HTTPException, Depends
 
 from wled_controller.api.auth import AuthRequired
 from wled_controller.api.dependencies import (
-    get_device_store,
     get_picture_source_store,
     get_pp_template_store,
-    get_processor_manager,
     get_template_store,
 )
 from wled_controller.api.schemas.common import (
@@ -32,8 +30,6 @@ from wled_controller.api.schemas.postprocessing import (
 )
 from wled_controller.core.capture_engines import EngineRegistry
 from wled_controller.core.filters import FilterRegistry, FilterInstance, ImagePool
-from wled_controller.core.processing.processor_manager import ProcessorManager
-from wled_controller.storage import DeviceStore
 from wled_controller.storage.template_store import TemplateStore
 from wled_controller.storage.postprocessing_template_store import PostprocessingTemplateStore
 from wled_controller.storage.picture_source_store import PictureSourceStore
@@ -168,8 +164,6 @@ async def test_pp_template(
     pp_store: PostprocessingTemplateStore = Depends(get_pp_template_store),
     stream_store: PictureSourceStore = Depends(get_picture_source_store),
     template_store: TemplateStore = Depends(get_template_store),
-    processor_manager: ProcessorManager = Depends(get_processor_manager),
-    device_store: DeviceStore = Depends(get_device_store),
 ):
     """Test a postprocessing template by capturing from a source stream and applying filters."""
     stream = None
@@ -227,19 +221,6 @@ async def test_pp_template(
                     detail=f"Engine '{capture_template.engine_type}' is not available on this system",
                 )
 
-            locked_device_id = processor_manager.get_display_lock_info(display_index)
-            if locked_device_id:
-                try:
-                    device = device_store.get_device(locked_device_id)
-                    device_name = device.name
-                except Exception:
-                    device_name = locked_device_id
-                raise HTTPException(
-                    status_code=409,
-                    detail=f"Display {display_index} is currently being captured by device '{device_name}'. "
-                           f"Please stop the device processing before testing.",
-                )
-
             stream = EngineRegistry.create_stream(
                 capture_template.engine_type, display_index, capture_template.engine_config
             )