refactor: move common/shaders/ to src/shaders/

Relocates shared WGSL shaders under src/ where all source code lives,
eliminating the top-level common/ directory.

- Update asset references in workspaces/main/assets.txt and workspaces/test/assets.txt
- Update docs: PROJECT_CONTEXT.md, ARCHITECTURE.md, WORKSPACE_SYSTEM.md, SHADER_REUSE_INVESTIGATION.md

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

1 files changed, 26 insertions, 0 deletions

diff --git a/src/shaders/compute/gen_noise.wgsl b/src/shaders/compute/gen_noise.wgsl
new file mode 100644
index 0000000..7b75f13
--- /dev/null
+++ b/src/shaders/compute/gen_noise.wgsl
@@ -0,0 +1,26 @@
+// GPU procedural noise texture generator.
+// Uses compute shader for parallel texture generation.
+
+#include "math/noise"
+
+struct NoiseParams {
+  width: u32,
+  height: u32,
+  seed: f32,
+  frequency: f32,
+}
+
+@group(0) @binding(0) var output_tex: texture_storage_2d<rgba8unorm, write>;
+@group(0) @binding(1) var<uniform> params: NoiseParams;
+
+@compute @workgroup_size(8, 8, 1)
+fn main(@builtin(global_invocation_id) id: vec3<u32>) {
+  if (id.x >= params.width || id.y >= params.height) { return; }
+
+  let uv = vec2f(f32(id.x) / f32(params.width),
+                 f32(id.y) / f32(params.height));
+  let p = uv * params.frequency + params.seed;
+  let noise = noise_2d(p);
+
+  textureStore(output_tex, id.xy, vec4f(noise, noise, noise, 1.0));
+}