Implement inference economics — BME token burn, provider payments, 6 contract updates

- InferenceProviderBridge: full BME payment flow (burn on request, mint on completion)
- ATNToken: authorized minter support for BME bridge
- TaskContract: inference task type with latency/quality tracking
- AutonetLib: InferenceTask struct for inference metadata
- ParticipantStaking: inference provider staking hooks

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: EightRice