docs: Fix EFFECT keyword syntax and add automation-friendly workflow

Fix EFFECT keyword format across all documentation and scripts - priority
modifier (+/=/–) is required but was missing from examples.

**Documentation fixes:**
- doc/HOWTO.md: Added missing + to EFFECT example
- doc/RECIPE.md: Added priority modifiers to examples
- tools/shadertoy/README.md: Fixed test path, clarified workflow
- tools/shadertoy/convert_shadertoy.py: Updated output instructions

**New automation guide:**
- doc/EFFECT_WORKFLOW.md: Complete step-by-step checklist for AI agents
  - Exact file paths and line numbers
  - Common issues and fixes
  - Asset ID naming conventions
  - CMakeLists.txt dual-section requirement
  - Test list instructions (post_process_effects vs scene_effects)

**Integration:**
- CLAUDE.md: Added EFFECT_WORKFLOW.md to Tier 2 (always loaded)
- doc/AI_RULES.md: Added "Adding Visual Effects" quick reference
- README.md: Added EFFECT_WORKFLOW.md to documentation list

**CMakeLists.txt:**
- Disabled incomplete cube_sphere_effect.cc (ShaderToy conversion WIP)

**Timeline:**
- Commented out incomplete CubeSphereEffect
- Removed obsolete constructor argument

Fixes #issue-with-effect-syntax

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

1 files changed, 1 insertions, 0 deletions

diff --git a/CLAUDE.md b/CLAUDE.md
index a52dfce..714339b 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -11,6 +11,7 @@
 @doc/HOWTO.md
 @doc/CONTRIBUTING.md
 @doc/AI_RULES.md
+@doc/EFFECT_WORKFLOW.md
 
 # ============================================
 # TIER 3: DESIGN DOCS (Load On-Demand)