feat(mirror): copy volumetric-disk params into uniform each frame

Extends mirror_params with the 9 new field assignments. DiskQuality enum
gains an as_u32() accessor for the WGSL tier selector. GPU now receives
live values; shader does not consume them yet.

src/params.rs

@@ -44,6 +44,16 @@ impl DiskQuality {
             DiskQuality::High => (5, 4, 3),
         }
     }
+
+    /// Tier as a u32 for the WGSL uniform selector.
+    pub fn as_u32(self) -> u32 {
+        match self {
+            DiskQuality::Off => 0,
+            DiskQuality::Low => 1,
+            DiskQuality::Medium => 2,
+            DiskQuality::High => 3,
+        }
+    }
 }
 
 /// All tunable black-hole parameters. Edited by the egui panel (Task 17),

src/render/plugin.rs

@@ -620,6 +620,15 @@ fn mirror_params(
         u.bloom_threshold = params.bloom_threshold;
         u.bloom_strength = params.bloom_strength;
         u.exposure = params.exposure;
+        u.disk_half_thickness = params.disk_half_thickness;
+        u.filament_freq = params.filament_freq;
+        u.filament_sharpness = params.filament_sharpness;
+        u.density_freq = params.density_freq;
+        u.density_strength = params.density_strength;
+        u.arm_count = params.arm_count;
+        u.arm_tightness = params.arm_tightness;
+        u.arm_strength = params.arm_strength;
+        u.disk_quality = params.disk_quality.as_u32();
     }
     // Update brightpass threshold (live-tunable).
     for (_, mat) in brightpass_materials.iter_mut() {