include info about asset sources file

docs/CODE_OF_CONDUCT.md

@@ -159,6 +159,30 @@ push_error("error")  # Use DebugManager.log_error() with context
 if debug_mode: print("debug info")  # Use DebugManager.log_debug()
 ```
 
+### Asset Management
+- **MANDATORY**: Every asset added to the project must be documented in `assets/sources.yaml`
+- Include complete source information, license details, and attribution requirements
+- Document any modifications made to original assets
+- Verify license compatibility with project usage before adding assets
+- Update sources.yaml in the same commit as adding the asset
+
+```gdscript
+# ✅ Correct asset addition workflow
+# 1. Add asset file to appropriate assets/ subdirectory
+# 2. Update assets/sources.yaml with complete metadata
+# 3. Commit both files together with descriptive message
+
+# Example sources.yaml entry:
+# audio:
+#   sfx:
+#     "button_click.wav":
+#       source: "https://freesound.org/people/user/sounds/12345/"
+#       license: "CC BY 3.0"
+#       attribution: "Button Click by SoundArtist"
+#       modifications: "Normalized volume, trimmed silence"
+#       usage: "UI button interactions"
+```
+
 ### Error Handling
 - Always check if resources loaded successfully
 - Use `DebugManager.log_error()` for critical failures
@@ -257,6 +281,26 @@ node.do_something()  # Could crash if node doesn't exist
 # Use autoloads instead
 ```
 
+### Asset Management Violations
+```gdscript
+# ❌ Don't add assets without documentation
+# Adding audio/new_music.mp3 without updating sources.yaml
+
+# ❌ Don't use assets without verifying licenses
+# Using copyrighted music without permission
+
+# ❌ Don't modify assets without documenting changes
+# Editing sprites without noting modifications in sources.yaml
+
+# ❌ Don't commit assets and documentation separately
+git add assets/sprites/new_sprite.png
+git commit -m "add sprite"  # Missing sources.yaml update
+
+# ✅ Correct approach
+git add assets/sprites/new_sprite.png assets/sources.yaml
+git commit -m "add new sprite with attribution"
+```
+
 ### Performance Issues
 ```gdscript
 # ❌ Don't search nodes repeatedly