test: cover orchestrator-learning and memory-router (#518)

Add unit tests for two previously-untested server modules:

- orchestrator-learning.ts (1% -> ~96% lines): candidate extraction,
  dedup/smartUpsert, aging/decay + journal compaction, finding-outcome
  triage learning, skill model, and decision history. Uses an in-memory
  OrchestratorMemory and a temp ORCHESTRATOR_DIR.
- orchestrator-memory-router.ts (28% -> 100% lines): every memory/trust/
  notification route plus auth and 400/empty-monitor edge cases, mounted
  on an ephemeral Express app.

Co-authored-by: Claude Opus 4 <noreply@anthropic.com>

Author: alari76