fix(shader_editor): sync CommonUniforms to current struct, fix layout

- Update CommonUniforms: remove _pad0/_pad1, add beat_time/beat_phase,
  move _pad to end (matches src/shaders/common_uniforms.wgsl)
- Fix JS uniform write order to match new layout
- Fix flex-direction: row override (common.css forced column, hiding editor)

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

1 files changed, 11 insertions, 9 deletions

diff --git a/tools/shader_editor/SHADER_EDITOR_DETAILS.md b/tools/shader_editor/SHADER_EDITOR_DETAILS.md
index b8bbb25..f6fdf2e 100644
--- a/tools/shader_editor/SHADER_EDITOR_DETAILS.md
+++ b/tools/shader_editor/SHADER_EDITOR_DETAILS.md
@@ -18,17 +18,17 @@ All shaders receive `CommonUniforms` at `@group(0) @binding(2)`:
 
 ```wgsl
 struct CommonUniforms {
-    resolution: vec2<f32>,      // Canvas width/height (1280, 720)
-    _pad0: f32,                 // Alignment padding
-    _pad1: f32,
+    resolution: vec2f,          // Canvas width/height (1280, 720)
     aspect_ratio: f32,          // resolution.x / resolution.y
     time: f32,                  // Seconds since start (resetable)
-    beat: f32,                  // Loop time 0.0→1.0 (period: 0.1-10s)
+    beat_time: f32,             // Absolute beat counter (currentTime / loopPeriod)
+    beat_phase: f32,            // Fractional beat 0.0→1.0 within current period
     audio_intensity: f32,       // Manual slider 0-1 or auto-pulse
+    _pad: f32,                  // Alignment padding
 };
 ```
 
-**Size:** 32 bytes (matches C++ `CommonPostProcessUniforms`)
+**Size:** 32 bytes (matches `src/shaders/common_uniforms.wgsl`)
 
 ## Bind Group Specification
 
@@ -85,12 +85,13 @@ Standard bindings for all shaders:
 @group(0) @binding(1) var txt: texture_2d<f32>;
 
 struct CommonUniforms {
-    resolution: vec2<f32>,
-    _pad0: f32, _pad1: f32,
+    resolution: vec2f,
     aspect_ratio: f32,
     time: f32,
-    beat: f32,
+    beat_time: f32,
+    beat_phase: f32,
     audio_intensity: f32,
+    _pad: f32,
 };
 @group(0) @binding(2) var<uniform> uniforms: CommonUniforms;
 
@@ -115,6 +116,7 @@ struct CommonUniforms {
 
 #include "common_uniforms"
 @group(0) @binding(2) var<uniform> uniforms: CommonUniforms;
+// uniforms.beat_phase → fractional beat, uniforms.beat_time → absolute beats
 
 @vertex fn vs_main(@builtin(vertex_index) i: u32) -> @builtin(position) vec4<f32> {
     var pos = array<vec2<f32>, 3>(
@@ -154,7 +156,7 @@ Animated gradient background with pulsing circle synced to `beat`:
     );
 
     // Pulsing circle
-    let d = length(uv) - 0.3 - 0.1 * sin(uniforms.beat * 6.28);
+    let d = length(uv) - 0.3 - 0.1 * sin(uniforms.beat_phase * 6.28);
     let circle = smoothstep(0.02, 0.0, d);
     let glow = 0.02 / (abs(d) + 0.02);