fix: resolve overlay provider slug mismatch in /model picker (#7373)

HERMES_OVERLAYS keys use models.dev IDs (e.g. 'github-copilot') but
_PROVIDER_MODELS curated lists and config.yaml use Hermes provider IDs
('copilot'). list_authenticated_providers() Section 2 was using the
overlay key directly for model lookups and is_current checks, causing:
- 0 models shown for copilot, kimi, kilo, opencode, vercel
- is_current never matching the config provider

Fix: build reverse mapping from PROVIDER_TO_MODELS_DEV to translate
overlay keys to Hermes slugs before curated list lookup and result
construction. Also adds 'kimi-for-coding' alias in auth.py so the
picker's returned slug resolves correctly in resolve_provider().

Fixes #5223. Based on work by HearthCore (#6492) and linxule (#6287).

Co-authored-by: HearthCore <HearthCore@users.noreply.github.com>
Co-authored-by: linxule <linxule@users.noreply.github.com>

tests/hermes_cli/test_overlay_slug_resolution.py

@@ -0,0 +1,83 @@
+"""Test that overlay providers with mismatched models.dev keys resolve correctly.
+
+HERMES_OVERLAYS keys may be models.dev IDs (e.g. "github-copilot") while
+_PROVIDER_MODELS and config.yaml use Hermes IDs ("copilot").  The slug
+resolution in list_authenticated_providers() Section 2 must bridge this gap.
+
+Covers: #5223, #6492
+"""
+
+import json
+import os
+from unittest.mock import patch
+
+import pytest
+
+from hermes_cli.model_switch import list_authenticated_providers
+
+
+# -- Copilot slug resolution (env var path) ----------------------------------
+
+@patch.dict(os.environ, {"COPILOT_GITHUB_TOKEN": "fake-ghu"}, clear=False)
+def test_copilot_uses_hermes_slug():
+    """github-copilot overlay should resolve to slug='copilot' with curated models."""
+    providers = list_authenticated_providers(current_provider="copilot")
+
+    copilot = next((p for p in providers if p["slug"] == "copilot"), None)
+    assert copilot is not None, "copilot should appear when COPILOT_GITHUB_TOKEN is set"
+    assert copilot["total_models"] > 0, "copilot should have curated models"
+    assert copilot["is_current"] is True
+
+    # Must NOT appear under the models.dev key
+    gh_copilot = next((p for p in providers if p["slug"] == "github-copilot"), None)
+    assert gh_copilot is None, "github-copilot slug should not appear (resolved to copilot)"
+
+
+@patch.dict(os.environ, {"COPILOT_GITHUB_TOKEN": "fake-ghu"}, clear=False)
+def test_copilot_no_duplicate_entries():
+    """Copilot must appear only once — not as both 'copilot' (section 1) and 'github-copilot' (section 2)."""
+    providers = list_authenticated_providers(current_provider="copilot")
+
+    copilot_slugs = [p["slug"] for p in providers if "copilot" in p["slug"]]
+    # Should have at most one copilot entry (may also have copilot-acp if creds exist)
+    copilot_main = [s for s in copilot_slugs if s == "copilot"]
+    assert len(copilot_main) == 1, f"Expected exactly one 'copilot' entry, got {copilot_main}"
+
+
+# -- kimi-for-coding alias in auth.py ----------------------------------------
+
+def test_kimi_for_coding_alias():
+    """resolve_provider('kimi-for-coding') should return 'kimi-coding'."""
+    from hermes_cli.auth import resolve_provider
+
+    result = resolve_provider("kimi-for-coding")
+    assert result == "kimi-coding"
+
+
+# -- Generic slug mismatch providers -----------------------------------------
+
+@patch.dict(os.environ, {"KIMI_API_KEY": "fake-key"}, clear=False)
+def test_kimi_for_coding_overlay_uses_hermes_slug():
+    """kimi-for-coding overlay should resolve to slug='kimi-coding'."""
+    providers = list_authenticated_providers(current_provider="kimi-coding")
+
+    kimi = next((p for p in providers if p["slug"] == "kimi-coding"), None)
+    assert kimi is not None, "kimi-coding should appear when KIMI_API_KEY is set"
+    assert kimi["is_current"] is True
+
+    # Must NOT appear under the models.dev key
+    kimi_mdev = next((p for p in providers if p["slug"] == "kimi-for-coding"), None)
+    assert kimi_mdev is None, "kimi-for-coding slug should not appear (resolved to kimi-coding)"
+
+
+@patch.dict(os.environ, {"KILOCODE_API_KEY": "fake-key"}, clear=False)
+def test_kilo_overlay_uses_hermes_slug():
+    """kilo overlay should resolve to slug='kilocode'."""
+    providers = list_authenticated_providers(current_provider="kilocode")
+
+    kilo = next((p for p in providers if p["slug"] == "kilocode"), None)
+    assert kilo is not None, "kilocode should appear when KILOCODE_API_KEY is set"
+    assert kilo["is_current"] is True
+
+    kilo_mdev = next((p for p in providers if p["slug"] == "kilo"), None)
+    assert kilo_mdev is None, "kilo slug should not appear (resolved to kilocode)"