Tier 3 baseline instrumentation and critical fix for test-induced
production database deletion. Tests using relative '.agentic-qe/memory.db'
paths were deleting the production DB during cleanup — now all test DB
paths use os.tmpdir(). Also fixes resetUnifiedMemory() cache leak and
process.cwd() bypasses in pull-agent and brain-handler.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>