fix(doctor): register vertex provider so hermes doctor recognizes Google Vertex AI (#65949)

[kyssta-exe]

Problem

When using model.provider: vertex for Google Vertex AI, running hermes doctor fails with:

model.provider 'vertex' is not a recognised provider

Vertex AI is a valid provider that works correctly at runtime (via runtime_provider.py → agent.vertex_adapter), but it was missing from both PROVIDER_REGISTRY and HERMES_OVERLAYS.

Root Cause

doctor.py builds its known-provider list from PROVIDER_REGISTRY.keys() + {"openrouter", "custom", "auto"}. Since vertex was never added to either:

1. PROVIDER_REGISTRY (auth.py) — so resolve_provider("vertex") raised AuthError
2. HERMES_OVERLAYS (providers.py) — so get_provider("vertex") returned None

Fix

• auth.py: Added vertex entry to PROVIDER_REGISTRY with auth_type="gcp_sdk" (parallel to bedrock using auth_type="aws_sdk"). Empty api_key_env_vars and base_url_env_var since Vertex uses GCP ADC / service account files, not static keys.
• providers.py: Added vertex to HERMES_OVERLAYS (transport="openai_chat", auth_type="gcp_sdk") so provider metadata resolves properly.
• providers.py: Added vertex aliases (google-vertex, vertex-ai, gcp-vertex, vertexai → vertex) to ALIASES.
• auth.py: Added same aliases to resolve_provider's _PROVIDER_ALIASES dict.
• providers.py: Added "vertex": "Google Vertex AI" to _LABEL_OVERRIDES.

Testing

• 66/66 doctor tests pass
• 151/151 runtime provider resolution tests pass
• All vertex aliases resolve correctly through both normalize_provider and resolve_provider
• get_provider("vertex") returns a proper ProviderDef with id="vertex"
• vertex is now visible in provider_catalog()

Fixes #65949

[tonydwb]

Looks good. No obvious issues found.

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Reviewed by Hermes Agent

[teknium1]

Thanks for tracing the doctor validation path; the reported false positive is present on current main.

Problems

• The patch creates a second Vertex auth description using gcp_sdk, but the registered Vertex profile uses auth_type="vertex" at plugins/model-providers/vertex/__init__.py:71, and the runtime client dispatches that value at agent/auxiliary_client.py:5300. Current main has no gcp_sdk handler.
• The diff adds no regression coverage for hermes doctor. Existing Vertex coverage is runtime/profile-only in tests/hermes_cli/test_vertex_provider.py:13-80; the provider-validation parameterization in tests/hermes_cli/test_doctor.py:513-565 does not include Vertex.

Suggested changes

• Teach hermes_cli/doctor.py:748-816 to recognize registered provider profiles (including their aliases) instead of duplicating Vertex into PROVIDER_REGISTRY and HERMES_OVERLAYS.
• Add a doctor regression test for model.provider: vertex and a google/... model slug, asserting both reported diagnostics are absent.

Automated hermes-sweeper review.

[kyssta-exe]

This PR has merge conflicts with the base branch and cannot be merged in its current state. Closing as part of automated PR maintenance — please rebase and re-open if the fix is still needed.