fix(memory): resolve Vitest false positive for expected rejection

[JosephDoUrden]

Summary

• Fix Vitest reporting a false-positive "Unhandled Errors" warning for the "should throw error for non-existent entity" test in the memory server
• Wrap the addObservations call in an async closure before asserting with .rejects.toThrow(), so Vitest's global unhandled rejection handler does not capture the expected error before the assertion intercepts it

Fixes #3073

Root cause

addObservations is an async function that throws synchronously inside a .map() callback. When passed directly to expect().rejects.toThrow(), the resulting Promise rejection is seen by Vitest's global rejection handler before the .rejects wrapper can intercept it. Wrapping in async () => { await ... } ensures the rejection is properly scoped.

Changes

• src/memory/__tests__/knowledge-graph.test.ts: Wrap the assertion in an async closure

Test plan

• All 45 memory server tests pass (npx vitest run)
• No "Unhandled Errors" warning in test output

AI Disclosure

AI assistance (Claude) was used for issue research. The implementation was written and reviewed by the author.