Add config file support for cpueval

[maryamtahhan]

Description

Add support for loading configuration from ~/.config/cpueval/config.yaml or ./.cpueval.yaml to reduce friction from setting environment variables every time.

Proposed Solution

# ~/.config/cpueval/config.yaml or .cpueval.yaml (project-level)
dut_hostname: ec2-52-16-102-83.eu-west-1.compute.amazonaws.com
loadgen_hostname: same  # Special value → copy dut_hostname
hf_token: hf_xxxxx
ansible_ssh_key: ~/eu-mtahhan.pem

defaults:
  cores: 16
  workload: chat

presets:
  aws-prod:
    dut_hostname: prod-dut
    vllm_container_image: custom:latest

Behavior

• Load order: default config → project .cpueval.yaml → env vars (env wins)
• --preset NAME loads presets.NAME section
• Doctor checks for config file and suggests creating one

Estimate

~4 hours

Original Source

Migrated from ROADMAP.md v0.2.0 item #1