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, 0 insertions, 66 deletions

diff --git a/common/shaders/render/raymarching.wgsl b/common/shaders/render/raymarching.wgsl
deleted file mode 100644
index 2d6616d..0000000
--- a/common/shaders/render/raymarching.wgsl
+++ /dev/null
@@ -1,66 +0,0 @@
-// Common functions for Signed Distance Field (SDF) raymarching.
-//
-// Required user-defined functions:
-//   - df(vec3f) -> f32
-//       Distance field for single-pass rendering (rayMarch, normal, shadow)
-//
-// For two-pass rendering with object IDs, see raymarching_id.wgsl
-//
-// Provided constants:
-//   TOLERANCE, MAX_RAY_LENGTH, MAX_RAY_MARCHES, NORM_OFF
-
-const TOLERANCE: f32 = 0.0005;
-const MAX_RAY_LENGTH: f32 = 20.0;
-const MAX_RAY_MARCHES: i32 = 80;
-const NORM_OFF: f32 = 0.005;
-
-// Computes the surface normal of the distance field at a point `pos`.
-fn normal(pos: vec3f) -> vec3f {
-  let eps = vec2f(NORM_OFF, 0.0);
-  var nor: vec3f;
-  nor.x = df(pos + eps.xyy) - df(pos - eps.xyy);
-  nor.y = df(pos + eps.yxy) - df(pos - eps.yxy);
-  nor.z = df(pos + eps.yyx) - df(pos - eps.yyx);
-  return normalize(nor);
-}
-
-// Performs the raymarching operation.
-// Returns the distance along the ray to the surface, or MAX_RAY_LENGTH if no surface is hit.
-fn rayMarch(ro: vec3f, rd: vec3f, tmin: f32) -> f32 {
-  var t = tmin;
-  for (var i = 0; i < MAX_RAY_MARCHES; i++) {
-    if (t > MAX_RAY_LENGTH) {
-      t = MAX_RAY_LENGTH;
-      break;
-    }
-    let d = df(ro + rd * t);
-    if (d < TOLERANCE) {
-      break;
-    }
-    t += d;
-  }
-  return t;
-}
-
-// Computes a soft shadow for a given point.
-fn shadow(lp: vec3f, ld: vec3f, mint: f32, maxt: f32) -> f32 {
-  let ds = 1.0 - 0.4;
-  var t = mint;
-  var nd = 1e6;
-  let soff = 0.05;
-  let smul = 1.5;
-  let MAX_SHD_MARCHES = 20;
-
-  for (var i = 0; i < MAX_SHD_MARCHES; i++) {
-    let p = lp + ld * t;
-    let d = df(p);
-    if (d < TOLERANCE || t >= maxt) {
-      let sd = 1.0 - exp(-smul * max(t / maxt - soff, 0.0));
-      return select(mix(sd, 1.0, smoothstep(0.0, 0.025, nd)), sd, t >= maxt);
-    }
-    nd = min(nd, d);
-    t += ds * d;
-  }
-  let sd = 1.0 - exp(-smul * max(t / maxt - soff, 0.0));
-  return sd;
-}