Feature/memory system improvement

[zfoong]

What and why?
Upgrading CraftBot's memory system from a memory.md into a graph-based "second brain". Memories and indexed files are now connected through LLM-extracted entities (inspired by Zep paper. This makes retrieval better, also cooler visualization since people enjoy seeing fancy graph.

Features and items added:

• Memories are automatically linked through shared entities (can be people, event, topics).
• Smarter memory recall: retrieval now combines meaning, keywords, and graph connections, with a boost for recent and well-connected memories
• Interactive memory graph page: a new UI panel (under workspace) to visually explore the agent's memories, their connections, and clusters
• File memories: users can pick files for the agent to index, and their content becomes part of the memory graph
• Configurable memory processing: processing kicks in once enough new events pile up, and the daily run skips quiet days
• Cleanup of outdated Living UI settings sections