Have a separate Kaizen Lite mode

[vinodmut]

In #26, we talked about no-code, low-code, and pro-code modes of using Kaizen.

I propose we call the no-code setup Kaizen Lite.

The Lite mode is easier to setup:

• No vector DB
• No MCP servers
• No need to access to agent logs or emit events to an observability tool
• No need to specify an LLM API key

But has a number of limitations:

• Inefficient context usage: it does entity extraction within the agent's context, not in a separate process.
• Scalability: It can't efficiently retrieve relevant entities when the entity set is large.
• Single-trajectory visibility: It only performs extraction on a single session, and can't glean insights for across sessions.
• Entity consolidation: It doesn't perform conflict resolution or garbage collection of entities.

Having a Lite mode makes it easier to communicate: onboard users with the Lite mode, when they hit limits they can move to the Pro mode.