The test 'falls back to most recent session when no to is provided' was
using resolveStorePath() which returns the real ~/.warelay/sessions.json.
This overwrote production session data with test values, causing session
fragmentation issues.
Changed to use a temp directory like other tests.
Tests were picking up real ~/.warelay/warelay.json with emojis and
prefixes (like "🦞"), causing test assertions to fail. Added proper
config mocks to all test files.
Changes:
- Mock loadConfig() in index.core.test.ts, inbound.media.test.ts,
monitor-inbox.test.ts
- Update test-helpers.ts default mock to disable all prefixes
- Tests now use clean config: no messagePrefix, no responsePrefix,
no timestamp, allowFrom=["*"]
This ensures tests validate core behavior without user-specific config.
The responsePrefix feature itself is already fully config-driven - this
only fixes test isolation.