fix(providers): support Anthropic proxy v1 endpoints

[helix4u]

What does this PR do?

Supports Anthropic-compatible proxy base URLs that already include the version segment, such as http://localhost:6655/anthropic/v1.

Hermes already supports custom/proxy endpoints and Anthropic Messages transport, but auto-detection only recognized URLs whose path ended exactly in /anthropic. Versioned proxy base URLs fell through to OpenAI chat-completions routing, which builds requests like /anthropic/v1/chat/completions instead of using the Anthropic Messages client.

This also makes model discovery respect the configured Anthropic/custom proxy base URL and Desktop-saved model.api_key, so the picker can query /anthropic/v1/models on the proxy instead of public Anthropic or an OpenAI-style catalog probe.

Adjacent PRs checked before this change: #43988, #37656, #30232, #37705. Those cover related URL/probe/base-url handling, but not the combined /anthropic/v1 transport detection plus configured proxy model catalog path fixed here.

Related Issue

None filed from the support thread.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• Tests (adding or improving test coverage)

Changes Made

• hermes_cli/runtime_provider.py: detect /anthropic/v1 base URLs as anthropic_messages while keeping deeper subpaths like /anthropic/v1/models out of transport detection.
• agent/auxiliary_client.py: mirror the same detection for auxiliary clients.
• agent/anthropic_adapter.py: strip a trailing /v1 before constructing the regular Anthropic SDK client, matching the bearer-hook path, so SDK requests still land on /anthropic/v1/messages rather than /anthropic/v1/v1/messages.
• hermes_cli/models.py: let Anthropic model discovery use configured model.base_url / model.api_key, and let custom provider discovery pass api_mode="anthropic_messages" for /anthropic/v1 proxy catalogs.
• Tests: added focused coverage for runtime detection, auxiliary detection, Anthropic SDK base URL normalization, and proxy catalog discovery.

How to Test

1. Configure an Anthropic-compatible proxy at http://localhost:6655/anthropic/v1.
2. Set the model provider/base URL through Desktop or config with api_mode: anthropic_messages.
3. Verify runtime calls use Anthropic Messages transport and model discovery probes http://localhost:6655/anthropic/v1/models with the saved key.
4. Run scripts/run_tests.sh -j 4 tests/hermes_cli/test_detect_api_mode_for_url.py tests/agent/test_auxiliary_transport_autodetect.py tests/agent/test_anthropic_adapter.py tests/hermes_cli/test_model_validation.py -- -q.

Checklist

Code

• I have read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this is not a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I have run pytest tests/ -q and all tests pass
• I have added tests for my changes (required for bug fixes, strongly encouraged for features)
• I have tested on my platform: WSL/Linux targeted test runner

Documentation & Housekeeping

• I have updated relevant documentation (README, docs/, docstrings) - or N/A
• I have updated cli-config.yaml.example if I added/changed config keys - or N/A
• I have updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows - or N/A
• I have considered cross-platform impact (Windows, macOS) per the compatibility guide - or N/A
• I have updated tool descriptions/schemas if I changed tool behavior - or N/A

Screenshots / Logs

Focused test run:

scripts/run_tests.sh -j 4 tests/hermes_cli/test_detect_api_mode_for_url.py tests/agent/test_auxiliary_transport_autodetect.py tests/agent/test_anthropic_adapter.py tests/hermes_cli/test_model_validation.py -- -q

Result: 4 files, 279 tests passed, 0 failed.

[liuhao1024]

Verified clean. Reviewed the full diff across all 8 files:

• URL normalization: build_anthropic_client strips trailing /v1 via regex — correct for the Anthropic SDK which appends /v1/messages itself. Test confirms https://proxy.example.com/anthropic/v1 → https://proxy.example.com/anthropic.
• Endpoint detection: _endpoint_speaks_anthropic_messages, _detect_api_mode_for_url, and _base_url_looks_like_anthropic_messages all use urlparse().path instead of endswith() — properly distinguishes /anthropic/v1 (base endpoint) from /anthropic/v1/models (subpath). Test coverage includes both cases.
• Live model catalog: _fetch_anthropic_models now accepts base_url and api_key parameters, and provider_model_ids("anthropic") passes them from config. validate_requested_model does the same. Custom endpoints with anthropic_messages api_mode now get proper model discovery.
• Test coverage: 6 new tests across 3 test files covering URL normalization, endpoint detection edge cases, and live catalog routing.

No dead variables, no broad exception catches hiding issues, no missing None guards.