Make client enhancements - batch memory creation, etc.

[abrookins]

Adds missing functionality and convenience methods to the Memory API Client to improve developer experience and provide better coverage of common use cases.

• ✅ Memory lifecycle management: promote_working_memories_to_long_term() method
• ✅ Batch operations: bulk_create_long_term_memories() with rate limiting
• ✅ Pagination utilities: search_all_long_term_memories() and search_all_memories()
• ✅ Client-side validation: validate_memory_record() and validate_search_filters()
• ✅ Enhanced convenience methods: update_working_memory_data(), append_messages_to_working_memory()

[Copilot]

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