Add Daylight Cycle value source type

New value source that outputs brightness (0-1) based on the daylight
color LUT, computing BT.601 luminance from the simulated sky color.
Supports real-time wall-clock mode or configurable simulation speed.

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

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

@@ -1,7 +1,7 @@
 """Value stream — runtime scalar signal generators.
 
 A ValueStream wraps a ValueSource config and computes a float (0.0–1.0)
-on demand via ``get_value()``.  Five concrete types:
+on demand via ``get_value()``.  Six concrete types:
 
   StaticValueStream      — returns a constant
   AnimatedValueStream    — evaluates a periodic waveform (sine/triangle/square/sawtooth)
@@ -9,6 +9,7 @@ on demand via ``get_value()``.  Five concrete types:
                            sensitivity and temporal smoothing
   TimeOfDayValueStream   — interpolates brightness along a 24h schedule (adaptive_time)
   SceneValueStream       — derives brightness from a picture source's frame luminance (adaptive_scene)
+  DaylightValueStream    — brightness derived from daylight cycle LUT (real-time or simulated)
 
 ValueStreams are cheap (trivial math or single poll), so they compute inline
 in the caller's processing loop — no background threads required.
@@ -541,6 +542,64 @@ class SceneValueStream(ValueStream):
                     self._live_stream = None
 
 
+# ---------------------------------------------------------------------------
+# Daylight
+# ---------------------------------------------------------------------------
+
+
+class DaylightValueStream(ValueStream):
+    """Brightness derived from the daylight color cycle LUT.
+
+    Computes BT.601 luminance from the RGB sky color at the current
+    simulated (or real-time) minute of day, then maps to [min, max].
+    Cheap inline computation — no background thread needed.
+    """
+
+    def __init__(
+        self,
+        speed: float = 1.0,
+        use_real_time: bool = False,
+        latitude: float = 50.0,
+        min_value: float = 0.0,
+        max_value: float = 1.0,
+    ):
+        from wled_controller.core.processing.daylight_stream import _get_daylight_lut
+        self._lut = _get_daylight_lut()
+        self._speed = speed
+        self._use_real_time = use_real_time
+        self._latitude = latitude
+        self._min = min_value
+        self._max = max_value
+        self._start_time = time.perf_counter()
+
+    def get_value(self) -> float:
+        if self._use_real_time:
+            now = datetime.now()
+            minute_of_day = now.hour * 60 + now.minute + now.second / 60.0
+        else:
+            t_elapsed = time.perf_counter() - self._start_time
+            cycle_seconds = 240.0 / max(self._speed, 0.01)
+            phase = (t_elapsed % cycle_seconds) / cycle_seconds
+            minute_of_day = phase * 1440.0
+
+        idx = int(minute_of_day) % 1440
+        r, g, b = self._lut[idx]
+
+        # BT.601 luminance → 0..1
+        luminance = (0.299 * float(r) + 0.587 * float(g) + 0.114 * float(b)) / 255.0
+
+        return self._min + luminance * (self._max - self._min)
+
+    def update_source(self, source: "ValueSource") -> None:
+        from wled_controller.storage.value_source import DaylightValueSource
+        if isinstance(source, DaylightValueSource):
+            self._speed = source.speed
+            self._use_real_time = source.use_real_time
+            self._latitude = source.latitude
+            self._min = source.min_value
+            self._max = source.max_value
+
+
 # ---------------------------------------------------------------------------
 # Manager
 # ---------------------------------------------------------------------------
@@ -635,6 +694,7 @@ class ValueStreamManager:
             AdaptiveValueSource,
             AnimatedValueSource,
             AudioValueSource,
+            DaylightValueSource,
             StaticValueSource,
         )
 
@@ -663,6 +723,15 @@ class ValueStreamManager:
                 audio_template_store=self._audio_template_store,
             )
 
+        if isinstance(source, DaylightValueSource):
+            return DaylightValueStream(
+                speed=source.speed,
+                use_real_time=source.use_real_time,
+                latitude=source.latitude,
+                min_value=source.min_value,
+                max_value=source.max_value,
+            )
+
         if isinstance(source, AdaptiveValueSource):
             if source.source_type == "adaptive_scene":
                 return SceneValueStream(