Add 5 procedural LED effects, gradient presets, auto-crop min aspect ratio, static source polling optimization

New features:
- Procedural effect source type with fire, meteor, plasma, noise, and aurora algorithms
  using palette LUT system and 1D value noise generator
- 12 predefined gradient presets (rainbow, sunset, ocean, forest, fire, lava, aurora,
  ice, warm, cool, neon, pastel) selectable from a dropdown in the gradient editor
- Auto-crop filter: min aspect ratio parameter to prevent false-positive cropping
  in dark scenes on ultrawide displays

Optimization:
- Static/gradient sources without animation: stream thread sleeps 0.25s instead of
  frame_time; processor repolls at frame_time instead of 5ms (~40x fewer iterations)
- Inverted isinstance checks in routes to test for PictureColorStripSource only

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

server/src/wled_controller/static/locales/en.json

@@ -589,6 +589,21 @@
   "color_strip.gradient.position": "Position (0.0–1.0)",
   "color_strip.gradient.bidir.hint": "Add a second color on the right side of this stop to create a hard edge in the gradient.",
   "color_strip.gradient.min_stops": "Gradient must have at least 2 stops",
+  "color_strip.gradient.preset": "Preset:",
+  "color_strip.gradient.preset.hint": "Load a predefined gradient palette. Selecting a preset replaces the current stops.",
+  "color_strip.gradient.preset.custom": "— Custom —",
+  "color_strip.gradient.preset.rainbow": "Rainbow",
+  "color_strip.gradient.preset.sunset": "Sunset",
+  "color_strip.gradient.preset.ocean": "Ocean",
+  "color_strip.gradient.preset.forest": "Forest",
+  "color_strip.gradient.preset.fire": "Fire",
+  "color_strip.gradient.preset.lava": "Lava",
+  "color_strip.gradient.preset.aurora": "Aurora",
+  "color_strip.gradient.preset.ice": "Ice",
+  "color_strip.gradient.preset.warm": "Warm",
+  "color_strip.gradient.preset.cool": "Cool",
+  "color_strip.gradient.preset.neon": "Neon",
+  "color_strip.gradient.preset.pastel": "Pastel",
   "color_strip.animation": "Animation",
   "color_strip.animation.type": "Effect:",
   "color_strip.animation.type.hint": "Animation effect to apply.",
@@ -617,5 +632,39 @@
   "color_strip.color_cycle.add_color": "+ Add Color",
   "color_strip.color_cycle.speed": "Speed:",
   "color_strip.color_cycle.speed.hint": "Cycle speed multiplier. 1.0 ≈ one full cycle every 20 seconds; higher values cycle faster.",
-  "color_strip.color_cycle.min_colors": "Color cycle must have at least 2 colors"
+  "color_strip.color_cycle.min_colors": "Color cycle must have at least 2 colors",
+  "color_strip.type.effect": "Effect",
+  "color_strip.type.effect.hint": "Procedural LED effects (fire, meteor, plasma, noise, aurora) generated in real time.",
+  "color_strip.effect.type": "Effect Type:",
+  "color_strip.effect.type.hint": "Choose the procedural algorithm.",
+  "color_strip.effect.fire": "Fire",
+  "color_strip.effect.fire.desc": "Cellular automaton simulating rising flames with heat diffusion",
+  "color_strip.effect.meteor": "Meteor",
+  "color_strip.effect.meteor.desc": "Bright head travels along the strip with an exponential-decay tail",
+  "color_strip.effect.plasma": "Plasma",
+  "color_strip.effect.plasma.desc": "Overlapping sine waves mapped to a palette — classic demo-scene effect",
+  "color_strip.effect.noise": "Noise",
+  "color_strip.effect.noise.desc": "Scrolling fractal value noise mapped to a palette",
+  "color_strip.effect.aurora": "Aurora",
+  "color_strip.effect.aurora.desc": "Layered noise bands that drift and blend — northern lights style",
+  "color_strip.effect.speed": "Speed:",
+  "color_strip.effect.speed.hint": "Speed multiplier for the effect animation (0.1 = very slow, 10.0 = very fast).",
+  "color_strip.effect.palette": "Palette:",
+  "color_strip.effect.palette.hint": "Color palette used to map effect values to RGB colors.",
+  "color_strip.effect.color": "Meteor Color:",
+  "color_strip.effect.color.hint": "Head color for the meteor effect.",
+  "color_strip.effect.intensity": "Intensity:",
+  "color_strip.effect.intensity.hint": "Effect intensity — controls spark rate (fire), tail decay (meteor), or brightness range (aurora).",
+  "color_strip.effect.scale": "Scale:",
+  "color_strip.effect.scale.hint": "Spatial scale — wave frequency (plasma), zoom level (noise), or band width (aurora).",
+  "color_strip.effect.mirror": "Mirror:",
+  "color_strip.effect.mirror.hint": "Bounce mode — the meteor reverses direction at strip ends instead of wrapping.",
+  "color_strip.palette.fire": "Fire",
+  "color_strip.palette.ocean": "Ocean",
+  "color_strip.palette.lava": "Lava",
+  "color_strip.palette.forest": "Forest",
+  "color_strip.palette.rainbow": "Rainbow",
+  "color_strip.palette.aurora": "Aurora",
+  "color_strip.palette.sunset": "Sunset",
+  "color_strip.palette.ice": "Ice"
 }