docs: add @APIResponse annotations to IRestUserMemoryStore

[ginccc]

Summary

IRestUserMemoryStore has 9 REST methods with @Operation but zero @APIResponse annotations. This is the largest single gap in OpenAPI coverage.

File

src/main/java/ai/labs/eddi/configs/properties/IRestUserMemoryStore.java

Pattern to follow

See IRestAgentStore.java for the established pattern. Common status codes:

• GET: 200, 404
• POST/PUT: 200 or 201, 400
• DELETE: 204, 404

Check the implementation (RestUserMemoryStore.java) to verify which status codes each method actually returns.

Acceptance criteria

• All 9 methods have appropriate @APIResponse annotations
• ./mvnw compile passes

[nightcityblade]

Hi, I'd like to work on this. I'll submit a PR shortly.