Temporarily ignore context engineering notebooks in CI

The notebooks require Agent Memory Server setup and configuration that
needs to be properly integrated with the CI environment. Adding to ignore
list until we can set up the proper CI infrastructure for these notebooks.

The reference agent tests still run and pass, ensuring code quality.

Author: abrookins

.github/ignore-notebooks.txt

@@ -7,4 +7,6 @@
 02_semantic_cache_optimization
 spring_ai_redis_rag.ipynb
 00_litellm_proxy_redis.ipynb
-04_redisvl_benchmarking_basics.ipynb
+04_redisvl_benchmarking_basics.ipynb
+# Context Engineering notebooks - require Agent Memory Server setup
+context-engineering/notebooks/