docs: streamline and consolidate markdown documentationHEADmain

Remove 530 lines of redundant content, archive dated docs, compact CNN
training sections, fix inconsistencies (effect count, test status).
Improves maintainability and reduces context load for AI agents.

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

1 files changed, 202 insertions, 0 deletions

diff --git a/doc/archive/FILE_HIERARCHY_CLEANUP_2026-02-13.md b/doc/archive/FILE_HIERARCHY_CLEANUP_2026-02-13.md
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+# File Hierarchy Cleanup - February 13, 2026
+
+## Summary
+
+Comprehensive reorganization of project file structure for improved maintainability and code reuse.
+
+---
+
+## Changes Implemented
+
+### 1. Application Entry Points → `src/app/`
+
+**Before:**
+```
+src/
+  main.cc
+  stub_main.cc
+  test_demo.cc
+```
+
+**After:**
+```
+src/app/
+  main.cc
+  stub_main.cc
+  test_demo.cc
+```
+
+**Impact:** Cleaner src/ directory, separates application code from libraries.
+
+---
+
+### 2. Workspace Reorganization
+
+**Before:**
+```
+workspaces/main/
+  assets/music/*.spec
+  shaders/*.wgsl
+  obj/*.obj
+
+assets/
+  demo.seq
+  music.track
+  originals/
+  common/
+  final/
+```
+
+**After:**
+```
+workspaces/{main,test}/
+  music/        # Audio samples (.spec)
+  weights/      # CNN binary weights (.bin)
+  obj/          # 3D models (.obj)
+  shaders/      # Workspace-specific WGSL only
+
+common/
+  shaders/      # Shared WGSL utilities
+    math/
+    render/
+    compute/
+
+tools/
+  originals/    # Source audio files
+  test_demo.seq
+  test_demo.track
+```
+
+**Removed:**
+- `assets/` directory (legacy structure)
+- `assets/common/` (replaced by `common/`)
+- `assets/final/` (superseded by workspaces)
+- `assets/originals/` → `tools/originals/`
+
+---
+
+### 3. Shared Shader System
+
+**Problem:** 36 duplicate shader files across workspaces (byte-identical).
+
+**Solution:** Implemented Option 1 from `SHADER_REUSE_INVESTIGATION.md`.
+
+**Structure:**
+```
+common/shaders/
+  common_uniforms.wgsl
+  lighting.wgsl
+  passthrough.wgsl
+  ray_box.wgsl
+  ray_triangle.wgsl
+  sdf_primitives.wgsl
+  skybox.wgsl
+  math/
+    common_utils.wgsl
+    noise.wgsl
+    sdf_shapes.wgsl
+    sdf_utils.wgsl
+  render/
+    lighting_utils.wgsl
+    scene_query_bvh.wgsl
+    scene_query_linear.wgsl
+    shadows.wgsl
+  compute/
+    gen_blend.wgsl
+    gen_grid.wgsl
+    gen_mask.wgsl
+    gen_noise.wgsl
+    gen_perlin.wgsl
+```
+
+**Reference in assets.txt:**
+```
+SHADER_COMMON_UNIFORMS, NONE, ../../common/shaders/common_uniforms.wgsl
+SHADER_MATH_NOISE, NONE, ../../common/shaders/math/noise.wgsl
+```
+
+**Asset Packer Enhancement:**
+- Added `#include <filesystem>` for path normalization
+- Implemented `lexically_normal()` to resolve `../../common/` references
+- Cross-platform path handling for workspace-relative includes
+
+---
+
+## Updated Files
+
+### Configuration
+- `workspaces/main/workspace.cfg` - Updated asset_dirs and shader_dirs
+- `workspaces/test/workspace.cfg` - Updated asset_dirs and shader_dirs
+- `workspaces/main/assets.txt` - Common shader references
+- `workspaces/test/assets.txt` - Common shader references
+
+### Build System
+- `cmake/DemoExecutables.cmake` - src/app/ paths, test_demo paths
+- `cmake/DemoCodegen.cmake` - Removed legacy fallback paths
+- `cmake/Validation.cmake` - Workspace shader paths
+
+### Tools
+- `tools/asset_packer.cc` - Filesystem path normalization
+- `scripts/gen_spectrograms.sh` - tools/originals/ paths
+- `scripts/train_cnn_v2_full.sh` - workspaces/main/weights/ paths
+- `training/export_cnn_v2_weights.py` - workspaces/main/weights/ paths
+
+### Application
+- `src/app/main.cc` - Hot-reload workspace paths
+
+---
+
+## Metrics
+
+**File Reduction:**
+- Removed 36 duplicate shader files
+- Deleted legacy assets/ structure (~70 files)
+- Net: ~100 files eliminated
+
+**Disk Space:**
+- Common shaders: 20 files
+- Per-workspace shaders: ~30-35 files
+- Saved: ~36 shader duplicates
+
+**Workspace Structure:**
+```
+workspaces/main/: 31 shaders (workspace-specific)
+workspaces/test/: 19 shaders (workspace-specific)
+common/: 20 shaders (shared)
+Total unique: 70 shaders (vs 106 before)
+```
+
+---
+
+## Benefits
+
+1. **Single Source of Truth:** Common shaders in one location
+2. **No Duplication:** Bug fixes apply everywhere automatically
+3. **Clear Separation:** Common vs workspace-specific code
+4. **Size Optimization:** Important for 64k target
+5. **Maintainability:** Easier to understand and modify
+6. **Workspace Isolation:** Each workspace still self-contained for specific content
+
+---
+
+## Migration Notes
+
+**For New Workspaces:**
+1. Create `workspaces/new_workspace/` with subdirs: `music/`, `weights/`, `obj/`, `shaders/`
+2. Reference common shaders: `../../common/shaders/...`
+3. Add workspace-specific shaders to local `shaders/`
+4. Update `workspace.cfg`: `asset_dirs = ["music/", "weights/", "obj/"]`
+
+**For Common Shader Changes:**
+- Edit files in `common/shaders/`
+- Changes apply to all workspaces immediately
+- Run full build to verify all workspaces
+
+---
+
+## Documentation Updated
+
+- `doc/WORKSPACE_SYSTEM.md` - New structure reflected
+- `doc/SHADER_REUSE_INVESTIGATION.md` - Implementation status
+- `doc/PROJECT_CONTEXT.md` - Current project state
+- `doc/FILE_HIERARCHY_CLEANUP_2026-02-13.md` - This document