feat/real cost reconciliation - #30

Summary

• capture provider-reported model-call costs directly from response usage when available, otherwise preserve pending generation IDs and reconcile them through the provider-local Generation API
• handle delayed billing records with bounded exponential retries, distinguish retryable and permanent failures, and persist credential-free per-attempt diagnostics in terminal Journal and ATIF metadata
• project resolved per-step costs, complete run totals, and explicit partial-cost state into ATIF trajectories without treating unknown costs as zero
• support both API-key and bearer-token authentication for reconciliation, and document the OpenRouter Anthropic-compatible configuration in both READMEs
• update the bilingual Event Journal protocol, 0.8.x development notes, changelog, and automated coverage for direct, delayed, failed, and auth-token reconciliation paths

Testing

• uv run pytest — 188 passed
• real OpenRouter smoke test confirmed two initial 404 responses followed by a resolved total_cost on the third lookup
• Harbor 0.21.0 trajectory validator accepted the generated ATIF artifact