Document config.yaml

[Ismael]

Based on the code, this seems to be the shape of the config, and it is expected to be at ~/.config/lumen/config.yaml

log_level: info          # string: debug | info | warn | error
max_chunk_tokens: 512    # int
freshness_ttl: 60s       # duration string (e.g. "30s", "5m")
reindex_timeout: 0s      # duration string; 0s = no timeout

servers:
  - backend: ollama        # required: "ollama" | "lmstudio"
    host: http://localhost:11434  # required: http/https URL
    model: nomic-embed-text       # required
    dims: 768              # int, optional — inferred from known models if omitted
    ctx_length: 2048       # int, optional — inferred from known models if omitted
    min_score: 0.0         # float, optional — inferred from dims if omitted

  - backend: lmstudio
    host: http://localhost:1234
    model: text-embedding-nomic-embed-text-v1.5
    dims: 768
    ctx_length: 2048
    min_score: 0.3