feat: Implement workspace system (Task #77)

Self-contained workspaces for parallel demo development.

Structure:
- workspaces/main,test - Demo-specific resources
- assets/common - Shared resources
- workspace.cfg - Configuration per workspace

CMake integration:
- DEMO_WORKSPACE option (defaults to main)
- cmake/ParseWorkspace.cmake - Config parser
- Workspace-relative asset/timeline/music paths

Migration:
- Main demo: demo.seq to workspaces/main/timeline.seq
- Test demo: test_demo.seq to workspaces/test/timeline.seq
- Common shaders: assets/common/shaders
- Workspace shaders: workspaces/*/shaders

Build:
cmake -B build -DDEMO_WORKSPACE=main
cmake -B build_test -DDEMO_WORKSPACE=test

All tests passing (36/36).

handoff(Claude): Task #77 workspace system complete. Both main and test workspaces build and pass all tests.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/workspaces/test/shaders/mesh_render.wgsl b/workspaces/test/shaders/mesh_render.wgsl
new file mode 100644
index 0000000..7390b06
--- /dev/null
+++ b/workspaces/test/shaders/mesh_render.wgsl
@@ -0,0 +1,58 @@
+#include "common_uniforms"
+#include "math/common_utils"
+
+@group(0) @binding(0) var<uniform> globals: GlobalUniforms;
+@group(0) @binding(1) var<storage, read> object_data: ObjectsBuffer;
+
+// Binding 2 is reserved for BVH (not used here but matches layout for simplicity)
+
+@group(0) @binding(3) var noise_tex: texture_2d<f32>;
+@group(0) @binding(4) var noise_sampler: sampler;
+@group(0) @binding(5) var sky_tex: texture_2d<f32>;
+
+struct VertexInput {
+    @location(0) position: vec3<f32>,
+    @location(1) normal: vec3<f32>,
+    @location(2) uv: vec2<f32>,
+};
+
+struct VertexOutput {
+    @builtin(position) clip_pos: vec4<f32>,
+    @location(0) world_pos: vec3<f32>,
+    @location(1) normal: vec3<f32>,
+    @location(2) uv: vec2<f32>,
+    @location(3) color: vec4<f32>,
+    @location(4) @interpolate(flat) instance_index: u32,
+};
+
+@vertex
+fn vs_main(in: VertexInput, @builtin(instance_index) instance_index: u32) -> VertexOutput {
+    let obj = object_data.objects[instance_index];
+    let world_pos = obj.model * vec4<f32>(in.position, 1.0);
+    
+    var out: VertexOutput;
+    out.clip_pos = globals.view_proj * world_pos;
+    out.world_pos = world_pos.xyz;
+    
+    // Transform normal from local to world space
+    out.normal = transform_normal(obj.inv_model, in.normal);
+    
+    out.uv = in.uv;
+    out.color = obj.color;
+    out.instance_index = instance_index;
+    return out;
+}
+
+#include "render/scene_query_mode"
+#include "render/shadows"
+#include "render/lighting_utils"
+
+@fragment
+fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
+    let light_dir = normalize(vec3<f32>(1.0, 1.0, 1.0));
+    
+    let shadow = calc_shadow(in.world_pos, light_dir, 0.05, 20.0, in.instance_index);
+    let lit_color = calculate_lighting(in.color.rgb, in.normal, in.world_pos, shadow);
+    
+    return vec4<f32>(lit_color, in.color.a);
+}
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