docs: refresh project architecture and repository rules

.gitignore

@@ -1,5 +1,9 @@
-# Operating-system files
+# Operating-system and editor metadata
 .DS_Store
+**/.idea/
+**/.vscode/
+*.swp
+*.tmp
 
 # Python environments and caches
 **/.venv/
@@ -9,28 +13,23 @@
 **/.mypy_cache/
 *.py[cod]
 
-# JavaScript dependencies and generated caches
+# JavaScript dependencies and generated builds
 **/node_modules/
 **/.next/
 **/.cache/
-models/
+**/dist/
 
-# Undownloaded upstream Git LFS demo/catalog pointers
+# Local frontend runtime data
+cad-agent-studio/config/llm.config.yaml
+cad-agent-studio/data/
+
+# Generated and upstream-heavy CAD assets
+/models/
 text-to-cad/assets/
 text-to-cad/benchmarks/*.gif
 text-to-cad/models/
 
-# Local editors and temporary files
-**/.idea/
-**/.vscode/
-*.swp
-*.tmp
-
-# Local frontend configuration and task artifacts
-cad-agent-studio/config/llm.config.yaml
-cad-agent-studio/data/
-
-# Protected DesignIR runtime data
+# DesignIR teacher data and runtime artifacts
 designir-pipeline/workspace/teacher/inbox/*
 !designir-pipeline/workspace/teacher/inbox/.gitkeep
 designir-pipeline/workspace/teacher/evidence/*