Fix filter_template expansion in test routes and select defaults

filter_template references were silently ignored in PP template test,
picture source test, and KC target test routes — they created a no-op
FilterTemplateFilter instead of expanding into the referenced template's
filters. Centralized expansion logic into PostprocessingTemplateStore.
resolve_filter_instances() and use it in all test routes + live stream
manager.

Also fixed empty template_id when adding filter_template filters: the
select dropdown showed the first template visually but onchange never
fired, saving "" instead. Now initializes with first choice's value and
auto-corrects stale/empty values at render time.

Other fixes: ScreenCapture dimensions now use actual image shape after
filter processing; brightness source label emoji updates.

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

server/src/wled_controller/core/filters/auto_crop.py

@@ -7,6 +7,9 @@ import numpy as np
 from wled_controller.core.filters.base import FilterOptionDef, PostprocessingFilter
 from wled_controller.core.filters.image_pool import ImagePool
 from wled_controller.core.filters.registry import FilterRegistry
+from wled_controller.utils import get_logger
+
+logger = get_logger(__name__)
 
 
 @FilterRegistry.register

server/src/wled_controller/core/processing/live_stream.py

@@ -256,8 +256,8 @@ class ProcessedLiveStream(LiveStream):
                         if idle_image is not _idle_src_buf:
                             processed = ScreenCapture(
                                 image=idle_image,
-                                width=cached_source_frame.width,
-                                height=cached_source_frame.height,
+                                width=idle_image.shape[1],
+                                height=idle_image.shape[0],
                                 display_index=cached_source_frame.display_index,
                             )
                             with self._frame_lock:
@@ -293,8 +293,8 @@ class ProcessedLiveStream(LiveStream):
 
                 processed = ScreenCapture(
                     image=image,
-                    width=source_frame.width,
-                    height=source_frame.height,
+                    width=image.shape[1],
+                    height=image.shape[0],
                     display_index=source_frame.display_index,
                 )
                 with self._frame_lock:

server/src/wled_controller/core/processing/live_stream_manager.py

@@ -239,44 +239,24 @@ class LiveStreamManager:
 
         return ProcessedLiveStream(source_live, filters), source_stream_id
 
-    def _resolve_filters(self, filter_instances, _visited=None):
-        """Recursively resolve filter instances, expanding filter_template refs.
+    def _resolve_filters(self, filter_instances):
+        """Resolve filter instances into instantiated PostprocessingFilter objects.
 
-        Args:
-            filter_instances: List of FilterInstance configs.
-            _visited: Set of template IDs already in the expansion stack
-                      (prevents circular references).
-
-        Returns:
-            List of instantiated PostprocessingFilter objects.
+        Expands filter_template references via the store, then creates instances.
         """
-        if _visited is None:
-            _visited = set()
+        if self._pp_template_store:
+            flat = self._pp_template_store.resolve_filter_instances(filter_instances)
+        else:
+            flat = [fi for fi in filter_instances if fi.filter_id != "filter_template"]
+
         resolved = []
-        for fi in filter_instances:
-            if fi.filter_id == "filter_template":
-                template_id = fi.options.get("template_id", "")
-                if not template_id or not self._pp_template_store:
-                    continue
-                if template_id in _visited:
-                    logger.warning(
-                        f"Circular filter template reference detected: {template_id}, skipping"
-                    )
-                    continue
-                try:
-                    pp = self._pp_template_store.get_template(template_id)
-                    _visited.add(template_id)
-                    resolved.extend(self._resolve_filters(pp.filters, _visited))
-                    _visited.discard(template_id)
-                except ValueError:
-                    logger.warning(f"Referenced filter template '{template_id}' not found, skipping")
-            else:
-                try:
-                    resolved.append(
-                        FilterRegistry.create_instance(fi.filter_id, fi.options)
-                    )
-                except ValueError as e:
-                    logger.warning(f"Skipping unknown filter '{fi.filter_id}': {e}")
+        for fi in flat:
+            try:
+                resolved.append(
+                    FilterRegistry.create_instance(fi.filter_id, fi.options)
+                )
+            except ValueError as e:
+                logger.warning(f"Skipping unknown filter '{fi.filter_id}': {e}")
         return resolved
 
     def _create_static_image_live_stream(self, config) -> StaticImageLiveStream: