CSS: add StaticColorStripSource type with auto-sized LED count

Introduces a new 'static' source type that fills all device LEDs with a
single constant RGB color — no screen capture or processing required.

- StaticColorStripSource storage model (color + led_count=0 auto-size)
- StaticColorStripStream: no background thread, configure() sizes to device
  LED count at processor start; hot-updates preserve runtime size
- ColorStripStreamManager dispatches static sources (no LiveStream needed)
- WledTargetProcessor calls stream.configure(device_led_count) on start
- API schemas/routes: source_type Literal["picture","static"]; color field;
  overlay/calibration-test endpoints return 400 for static
- Frontend: type selector modal, color picker, type-aware card rendering
  (🎨 icon + color swatch), LED count field hidden for static type
- Locale keys: color_strip.type, color_strip.static_color (en + ru)

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

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

@@ -26,7 +26,7 @@ from wled_controller.core.capture.calibration import (
 )
 from wled_controller.core.capture.screen_capture import get_available_displays
 from wled_controller.core.processing.processor_manager import ProcessorManager
-from wled_controller.storage.color_strip_source import PictureColorStripSource
+from wled_controller.storage.color_strip_source import PictureColorStripSource, StaticColorStripSource
 from wled_controller.storage.color_strip_store import ColorStripStore
 from wled_controller.storage.picture_source import ProcessedPictureSource, ScreenCapturePictureSource
 from wled_controller.storage.picture_source_store import PictureSourceStore
@@ -57,6 +57,7 @@ def _css_to_response(source, overlay_active: bool = False) -> ColorStripSourceRe
         interpolation_mode=getattr(source, "interpolation_mode", None),
         led_count=getattr(source, "led_count", 0),
         calibration=calibration,
+        color=getattr(source, "color", None),
         description=source.description,
         overlay_active=overlay_active,
         created_at=source.created_at,
@@ -117,6 +118,7 @@ async def create_color_strip_source(
             interpolation_mode=data.interpolation_mode,
             led_count=data.led_count,
             calibration=calibration,
+            color=data.color,
             description=data.description,
         )
         return _css_to_response(source)
@@ -169,6 +171,7 @@ async def update_color_strip_source(
             interpolation_mode=data.interpolation_mode,
             led_count=data.led_count,
             calibration=calibration,
+            color=data.color,
             description=data.description,
         )
 
@@ -255,6 +258,11 @@ async def test_css_calibration(
         if body.edges:
             try:
                 source = store.get_source(source_id)
+                if isinstance(source, StaticColorStripSource):
+                    raise HTTPException(
+                        status_code=400,
+                        detail="Calibration test is not applicable for static color strip sources",
+                    )
                 if isinstance(source, PictureColorStripSource) and source.calibration:
                     calibration = source.calibration
             except ValueError as e:
@@ -296,6 +304,8 @@ async def start_css_overlay(
     """Start screen overlay visualization for a color strip source."""
     try:
         source = store.get_source(source_id)
+        if isinstance(source, StaticColorStripSource):
+            raise HTTPException(status_code=400, detail="Overlay is not supported for static color strip sources")
         if not isinstance(source, PictureColorStripSource):
             raise HTTPException(status_code=400, detail="Overlay only supported for picture color strip sources")
         if not source.calibration: