feat(memory): add tool annotations to all knowledge graph tools (#3874)

feat(memory): add tool annotations to all knowledge graph tools (#3874) Add MCP ToolAnnotations to all 9 tools in the memory server, matching the annotation coverage already present in server-filesystem, server-git, server-time, and server-sequential-thinking. - Read tools (read_graph, search_nodes, open_nodes): read-only, idempotent - Write tools (create_entities, create_relations, add_observations): non-destructive - Delete tools (delete_entities, delete_observations, delete_relations): destructive, idempotent - All tools: openWorldHint=false (local JSONL file operations only) Co-authored-by: Ola Hungerford