feat: native Anthropic provider with Claude Code credential auto-discovery
Add Anthropic as a first-class inference provider, bypassing OpenRouter
for direct API access. Uses the native Anthropic SDK with a full format
adapter (same pattern as the codex_responses api_mode).
## Auth (three methods, priority order)
1. ANTHROPIC_API_KEY env var (regular API key, sk-ant-api-*)
2. ANTHROPIC_TOKEN / CLAUDE_CODE_OAUTH_TOKEN env var (setup-token, sk-ant-oat-*)
3. Auto-discovery from ~/.claude/.credentials.json (Claude Code subscription)
- Reads Claude Code's OAuth credentials
- Checks token expiry with 60s buffer
- Setup tokens use Bearer auth + anthropic-beta: oauth-2025-04-20 header
- Regular API keys use standard x-api-key header
## Changes by file
### New files
- agent/anthropic_adapter.py — Client builder, message/tool/response
format conversion, Claude Code credential reader, token resolver.
Handles system prompt extraction, tool_use/tool_result blocks,
thinking/reasoning, orphaned tool_use cleanup, cache_control.
- tests/test_anthropic_adapter.py — 36 tests covering all adapter logic
### Modified files
- pyproject.toml — Add anthropic>=0.39.0 dependency
- hermes_cli/auth.py — Add 'anthropic' to PROVIDER_REGISTRY with
three env vars, plus 'claude'/'claude-code' aliases
- hermes_cli/models.py — Add model catalog, labels, aliases, provider order
- hermes_cli/main.py — Add 'anthropic' to --provider CLI choices
- hermes_cli/runtime_provider.py — Add Anthropic branch returning
api_mode='anthropic_messages' (before generic api_key fallthrough)
- hermes_cli/setup.py — Add Anthropic setup wizard with Claude Code
credential auto-discovery, model selection, OpenRouter tools prompt
- agent/auxiliary_client.py — Add claude-haiku-4-5 as aux model
- agent/model_metadata.py — Add bare Claude model context lengths
- run_agent.py — Add anthropic_messages api_mode:
* Client init (Anthropic SDK instead of OpenAI)
* API call dispatch (_anthropic_client.messages.create)
* Response validation (content blocks)
* finish_reason mapping (stop_reason -> finish_reason)
* Token usage (input_tokens/output_tokens)
* Response normalization (normalize_anthropic_response)
* Client interrupt/rebuild
* Prompt caching auto-enabled for native Anthropic
- tests/test_run_agent.py — Update test_anthropic_base_url_accepted to
expect native routing, add test_prompt_caching_native_anthropic
5e12442b4b