Provide `config-example.yml` for ema

[Myriad-Dreamin]

config-example.yml is for mini-agent.py instead of ema: https://github.com/EmaFanClub/EverMemoryArchive/blob/c86ca3fcffe0f5919c89d636e3928d675f92e985/config/config-example.yaml

• update config-example.yml
• vitest that config-example.yml are always parsed into expected configurations.