[M2] Loki Configuration Model

[miciav]

Description

Add Loki settings to configuration system.

Files to modify

• lb_runner/benchmark_config.py
• lb_common/logging.py

Config structure

class LokiConfig(BaseModel):
    enabled: bool = False
    endpoint: str = "http://localhost:3100"
    labels: Dict[str, str] = {}
    batch_size: int = 100
    flush_interval_ms: int = 1000
    timeout_seconds: int = 5
    max_retries: int = 3
    retention_days: int = 1  # Minimo per risparmiare spazio

Acceptance criteria

• Config model with validation
• Environment variable overrides (LB_LOKI_ENDPOINT, etc.)
• Integration with configure_logging()

Milestone: M2 - Loki Push Integration
Issue: 2.2

[miciav]

Implemented LokiConfig in lb_runner/models/config.py (platform/run defaults).