Remediation: Implement shared common/shaders/ directory

Eliminates 36 duplicate shader files across workspaces.

Structure:
- common/shaders/{math,render,compute}/ - Shared utilities (20 files)
- workspaces/*/shaders/ - Workspace-specific only

Changes:
- Created common/shaders/ with math, render, compute subdirectories
- Moved 20 common shaders from workspaces to common/
- Removed duplicates from test workspace
- Updated assets.txt: ../../common/shaders/ references
- Enhanced asset_packer.cc: filesystem path normalization for ../ resolution

Implementation: Option 1 from SHADER_REUSE_INVESTIGATION.md
- Single source of truth for common code
- Workspace references via relative paths
- Path normalization in asset packer

handoff(Claude): Common shader directory implemented

1 files changed, 56 insertions, 0 deletions

diff --git a/common/shaders/render/scene_query_linear.wgsl b/common/shaders/render/scene_query_linear.wgsl
new file mode 100644
index 0000000..0497a40
--- /dev/null
+++ b/common/shaders/render/scene_query_linear.wgsl
@@ -0,0 +1,56 @@
+#include "math/sdf_shapes"
+#include "math/sdf_utils"
+
+fn get_dist(p: vec3<f32>, obj_params: vec4<f32>) -> f32 {
+    let obj_type = obj_params.x;
+    if (obj_type == 1.0) { return length(p) - 1.0; } // Unit Sphere
+    if (obj_type == 2.0) { return sdBox(p, vec3<f32>(1.0)); } // Unit Box
+    if (obj_type == 3.0) { return sdTorus(p, vec2<f32>(1.0, 0.4)); } // Unit Torus
+    if (obj_type == 4.0) { return sdPlane(p, vec3<f32>(0.0, 1.0, 0.0), 0.0); }
+    if (obj_type == 5.0) { return sdBox(p, obj_params.yzw); } // MESH AABB
+    return 100.0;
+}
+
+fn map_scene(p: vec3<f32>, skip_idx: u32) -> f32 {
+
+    var d = 1000.0;
+
+    let num_objects = arrayLength(&object_data.objects);
+
+    for (var i = 0u; i < num_objects; i++) {
+
+        if (i == skip_idx) { continue; }
+
+        let obj = object_data.objects[i];
+
+        let q = (obj.inv_model * vec4<f32>(p, 1.0)).xyz;
+
+        
+
+        // Extract scale factors from the model matrix
+
+        let sx = length(obj.model[0].xyz);
+
+        let sy = length(obj.model[1].xyz);
+
+        let sz = length(obj.model[2].xyz);
+
+        
+
+        var s = min(sx, min(sy, sz));
+
+        if (obj.params.x == 4.0) {
+
+            s = sy; // Plane normal is (0,1,0) in local space
+
+        }
+
+        
+
+        d = min(d, get_dist(q, obj.params) * s);
+
+    }
+
+    return d;
+
+}