chore: strip demo/deployment targets from Makefile, add .claude/ to .gitignore

Enforce strict separation: core platform PR must not contain demo scripts,
deployment guides, staging infra, or spring-boot demo targets. Only core
LFS additions remain (build-sdk, docker-build-lfs-proxy, test-lfs-proxy-broker).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: kamir

.gitignore

@@ -58,6 +58,7 @@ spark-warehouse/
 *.swp
 *.swo
 .DS_Store
+.claude/
 
 # Addon processor artifacts
 addons/processors/**/bin/