fix: abort auto-recall retrieval on timeout

[TurboTheTurtle]

Summary

• abort in-flight auto-recall retrieval work when the outer timeout fires
• thread AbortSignal through retrieveWithRetry and retriever vector/hybrid embedding paths
• suppress expected post-timeout abort noise while keeping the existing timeout warning

Fixes #643

Tests

• node --test test/auto-recall-timeout.test.mjs
• node test/retriever-rerank-regression.mjs
• npm run build