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/core/audio/audio_capture.py

@@ -253,13 +253,27 @@ class AudioCaptureManager:
         """List available audio devices from all registered engines.
 
         Returns list of dicts with device info, each tagged with engine_type.
+        Deduplicates by (name, is_loopback), keeping the entry from the
+        highest-priority engine.
         """
+        # Collect from all engines, sorted by descending priority
+        engines = [
+            (engine_class.ENGINE_PRIORITY, engine_type, engine_class)
+            for engine_type, engine_class in AudioEngineRegistry.get_all_engines().items()
+        ]
+        engines.sort(key=lambda x: x[0], reverse=True)
+
+        seen: set = set()
         result = []
-        for engine_type, engine_class in AudioEngineRegistry.get_all_engines().items():
+        for _priority, engine_type, engine_class in engines:
             try:
                 if not engine_class.is_available():
                     continue
                 for dev in engine_class.enumerate_devices():
+                    key = (dev.name, dev.is_loopback)
+                    if key in seen:
+                        continue
+                    seen.add(key)
                     result.append({
                         "index": dev.index,
                         "name": dev.name,

server/src/wled_controller/core/audio/wasapi_engine.py

@@ -163,34 +163,56 @@ class WasapiEngine(AudioCaptureEngine):
             wasapi_idx = wasapi_info["index"]
 
             result = []
+            loopback_names: set = set()
             device_count = pa.get_device_count()
+
+            # First pass: collect input devices.  PyAudioWPatch creates
+            # dedicated loopback input endpoints for output devices; these
+            # show up as input devices whose name already contains
+            # "[Loopback]".  We mark them as loopback and remember the name
+            # so the second pass won't duplicate them.
             for i in range(device_count):
                 dev = pa.get_device_info_by_index(i)
                 if dev["hostApi"] != wasapi_idx:
                     continue
+                if dev["maxInputChannels"] <= 0:
+                    continue
 
-                is_input = dev["maxInputChannels"] > 0
-                is_output = dev["maxOutputChannels"] > 0
+                name = dev["name"]
+                is_loopback = "[Loopback]" in name
+                if is_loopback:
+                    loopback_names.add(name)
 
-                if is_input:
-                    result.append(AudioDeviceInfo(
-                        index=i,
-                        name=dev["name"],
-                        is_input=True,
-                        is_loopback=False,
-                        channels=dev["maxInputChannels"],
-                        default_samplerate=dev["defaultSampleRate"],
-                    ))
+                result.append(AudioDeviceInfo(
+                    index=i,
+                    name=name,
+                    is_input=True,
+                    is_loopback=is_loopback,
+                    channels=dev["maxInputChannels"],
+                    default_samplerate=dev["defaultSampleRate"],
+                ))
 
-                if is_output:
-                    result.append(AudioDeviceInfo(
-                        index=i,
-                        name=f"{dev['name']} [Loopback]",
-                        is_input=False,
-                        is_loopback=True,
-                        channels=dev["maxOutputChannels"],
-                        default_samplerate=dev["defaultSampleRate"],
-                    ))
+            # Second pass: add loopback entries for output devices that
+            # don't already have a dedicated loopback input endpoint.
+            for i in range(device_count):
+                dev = pa.get_device_info_by_index(i)
+                if dev["hostApi"] != wasapi_idx:
+                    continue
+                if dev["maxOutputChannels"] <= 0:
+                    continue
+
+                loopback_name = f"{dev['name']} [Loopback]"
+                if loopback_name in loopback_names:
+                    continue  # already covered by a dedicated loopback endpoint
+
+                result.append(AudioDeviceInfo(
+                    index=i,
+                    name=loopback_name,
+                    is_input=False,
+                    is_loopback=True,
+                    channels=dev["maxOutputChannels"],
+                    default_samplerate=dev["defaultSampleRate"],
+                ))
 
             return result