Show pipeline timing breakdown for non-picture source targets

Non-picture sources (static, gradient, color_cycle) returned empty
timing from get_last_timing(), causing timing_total_ms to be null and
hiding the entire timing section in the UI. Now timing_total_ms falls
back to send_ms when no CSS pipeline timing exists. Frontend timing
bar/legend segments are conditionally rendered to avoid null labels.

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

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

@@ -245,10 +245,13 @@ class WledTargetProcessor(TargetProcessor):
         extract_ms = round(css_timing.get("extract_ms", 0), 1) if css_timing else None
         map_ms = round(css_timing.get("map_leds_ms", 0), 1) if css_timing else None
         smooth_ms = round(css_timing.get("smooth_ms", 0), 1) if css_timing else None
-        total_ms = (
-            round(css_timing.get("total_ms", 0) + metrics.timing_send_ms, 1)
-            if css_timing else None
-        )
+        if css_timing:
+            total_ms = round(css_timing.get("total_ms", 0) + metrics.timing_send_ms, 1)
+        elif self._is_running and send_ms is not None:
+            # Non-picture sources have no CSS pipeline timing — total = send only
+            total_ms = send_ms
+        else:
+            total_ms = None
 
         return {
             "target_id": self._target_id,