fix(shaders): deduplicate VertexOutput/vs_main via render/fullscreen_uv_vs snippet

- Fix vs_main return type (VertexOutput, not vec4<f32>)
- Fix #include paths in passthrough, gaussian_blur, heptagon, combined_postprocess
- ShaderComposer: assert + suggest correct path on missing #include (non-STRIP_ALL)
- VerifyIncludes: upgrade WARNING to ERROR + assert, add "did you mean?" hint

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

1 files changed, 1 insertions, 14 deletions

diff --git a/common/shaders/heptagon.wgsl b/common/shaders/heptagon.wgsl
index 078978a..519dce5 100644
--- a/common/shaders/heptagon.wgsl
+++ b/common/shaders/heptagon.wgsl
@@ -1,23 +1,10 @@
 // Heptagon shader for Sequence v2
 #include "sequence_uniforms"
+#include "render/fullscreen_uv_vs"  // <- VertexOutput + vs_main
 
 // Standard v2 post-process layout (bindings 0,1 unused for scene effects)
 @group(0) @binding(2) var<uniform> uniforms: UniformsSequenceParams;
 
-struct VertexOutput {
-    @builtin(position) position: vec4<f32>,
-    @location(0) uv: vec2<f32>,
-};
-
-@vertex fn vs_main(@builtin(vertex_index) vid: u32) -> VertexOutput {
-    var out: VertexOutput;
-    let x = f32((vid & 1u) << 1u);
-    let y = f32((vid & 2u));
-    out.position = vec4<f32>(x * 2.0 - 1.0, 1.0 - y * 2.0, 0.0, 1.0);
-    out.uv = vec2<f32>(x, y);
-    return out;
-}
-
 fn sdf_heptagon(p: vec2<f32>, r: f32) -> f32 {
     let an = 3.141593 / 7.0;  // PI/7 for heptagon
     let acs = vec2<f32>(cos(an), sin(an));