feat(/model): merge models.dev entries for lesser-loved providers (#14221)

New and newer models from models.dev now surface automatically in
/model (both hermes model CLI and the gateway Telegram/Discord picker)
for a curated set of secondary providers — no Hermes release required
when the registry publishes a new model.

Primary user-visible fix: on OpenCode Go, typing '/model mimo-v2.5-pro'
no longer silently fuzzy-corrects to 'mimo-v2-pro'. The exact match
against the merged models.dev catalog wins.

Scope (opt-in frozenset _MODELS_DEV_PREFERRED in hermes_cli/models.py):
  opencode-go, opencode-zen, deepseek, kilocode, fireworks, mistral,
  togetherai, cohere, perplexity, groq, nvidia, huggingface, zai,
  gemini, google.

Explicitly NOT merged:
  - openrouter and nous (never): curated list is already a hand-picked
    subset / Portal is source of truth.
  - xai, xiaomi, minimax, minimax-cn, kimi-coding, kimi-coding-cn,
    alibaba, qwen-oauth (per-project decision to keep curated-only).
  - providers with dedicated live-endpoint paths (copilot, anthropic,
    ai-gateway, ollama-cloud, custom, stepfun, openai-codex) — those
    paths already handle freshness themselves.

Changes:
  - hermes_cli/models.py: add _MODELS_DEV_PREFERRED + _merge_with_models_dev
    helper. provider_model_ids() branches on the set at its curated-fallback
    return. Merge is models.dev-first, curated-only extras appended,
    case-insensitive dedup, graceful fallback when models.dev is offline.
  - hermes_cli/model_switch.py: list_authenticated_providers() calls the
    same merge in both its code paths (PROVIDER_TO_MODELS_DEV loop +
    HERMES_OVERLAYS loop). Picker AND validation-fallback both see
    fresh entries.
  - tests/hermes_cli/test_models_dev_preferred_merge.py (new): 13 tests —
    merge-helper unit tests (empty/raise/order/dedup), opencode-go/zen
    behavior, openrouter+nous explicitly guarded from merge.
  - tests/hermes_cli/test_opencode_go_in_model_list.py: converted from
    snapshot-style assertion to a behavior-based floor check, so it
    doesn't break when models.dev publishes additional opencode-go
    entries.

Addresses a report from @pfanis via Telegram: newer Xiaomi variants
on OpenCode Go weren't appearing in the /model picker, and /model
was silently routing requests for new variants to older ones.

tests/hermes_cli/test_models_dev_preferred_merge.py

@@ -0,0 +1,124 @@
+"""Tests for the models.dev-preferred merge behavior in provider_model_ids
+and list_authenticated_providers.
+
+These guard the contract:
+
+  * For providers in ``_MODELS_DEV_PREFERRED`` (opencode-go, opencode-zen,
+    xiaomi, deepseek, smaller inference providers), both the CLI model
+    picker path (``provider_model_ids``) and the gateway ``/model`` picker
+    path (``list_authenticated_providers``) merge fresh models.dev entries
+    on top of the curated static list.
+  * OpenRouter and Nous Portal are NEVER merged — they keep their curated
+    (OpenRouter) or live-Portal (Nous) semantics.
+  * If models.dev is unreachable (offline / CI), the curated list is the
+    fallback — no crash, no empty list.
+
+Merging is what lets new models (e.g. ``mimo-v2.5-pro`` on opencode-go)
+appear in ``/model`` without a Hermes release.
+"""
+
+import os
+from unittest.mock import patch
+
+import pytest
+
+from hermes_cli.models import (
+    _MODELS_DEV_PREFERRED,
+    _merge_with_models_dev,
+    provider_model_ids,
+)
+
+
+class TestMergeHelper:
+    def test_merge_empty_mdev_returns_curated(self):
+        """When models.dev returns nothing, curated list is preserved verbatim."""
+        with patch("agent.models_dev.list_agentic_models", return_value=[]):
+            out = _merge_with_models_dev("opencode-go", ["mimo-v2-pro", "kimi-k2.6"])
+        assert out == ["mimo-v2-pro", "kimi-k2.6"]
+
+    def test_merge_mdev_raises_returns_curated(self):
+        """Offline / broken models.dev must not break the catalog path."""
+        def boom(_provider):
+            raise RuntimeError("network down")
+
+        with patch("agent.models_dev.list_agentic_models", side_effect=boom):
+            out = _merge_with_models_dev("opencode-go", ["mimo-v2-pro"])
+        assert out == ["mimo-v2-pro"]
+
+    def test_merge_mdev_first_then_curated_extras(self):
+        """models.dev entries come first; curated-only entries are appended."""
+        mdev = ["mimo-v2.5-pro", "mimo-v2-pro", "kimi-k2.6"]
+        curated = ["kimi-k2.6", "kimi-k2.5", "mimo-v2-pro"]  # kimi-k2.5 is curated-only
+        with patch("agent.models_dev.list_agentic_models", return_value=mdev):
+            out = _merge_with_models_dev("opencode-go", curated)
+        # models.dev entries first (in order), then curated-only entries
+        assert out == ["mimo-v2.5-pro", "mimo-v2-pro", "kimi-k2.6", "kimi-k2.5"]
+
+    def test_merge_case_insensitive_dedup(self):
+        """Dedup is case-insensitive but preserves the first occurrence's casing."""
+        mdev = ["MiniMax-M2.7"]
+        curated = ["minimax-m2.7", "minimax-m2.5"]
+        with patch("agent.models_dev.list_agentic_models", return_value=mdev):
+            out = _merge_with_models_dev("minimax", curated)
+        # models.dev casing wins since it came first
+        assert out == ["MiniMax-M2.7", "minimax-m2.5"]
+
+
+class TestProviderModelIdsPreferred:
+    def test_opencode_go_is_preferred(self):
+        assert "opencode-go" in _MODELS_DEV_PREFERRED
+
+    def test_opencode_go_includes_fresh_models_dev_entries(self):
+        """provider_model_ids('opencode-go') adds models.dev entries on top."""
+        mdev = ["mimo-v2.5-pro", "mimo-v2.5", "mimo-v2-pro", "kimi-k2.6"]
+        with patch("agent.models_dev.list_agentic_models", return_value=mdev):
+            out = provider_model_ids("opencode-go")
+        # Fresh models must surface (this is exactly the reported bug fix:
+        # mimo-v2.5-pro should be pickable on opencode-go).
+        assert "mimo-v2.5-pro" in out
+        assert "mimo-v2.5" in out
+        # Curated entries are still present.
+        assert "mimo-v2-pro" in out
+        assert "kimi-k2.6" in out
+
+    def test_opencode_go_offline_falls_back_to_curated(self):
+        """Offline models.dev → curated-only list, no crash."""
+        with patch("agent.models_dev.list_agentic_models", return_value=[]):
+            out = provider_model_ids("opencode-go")
+        # Curated floor (see hermes_cli/models.py _PROVIDER_MODELS["opencode-go"])
+        assert "mimo-v2-pro" in out
+        assert "kimi-k2.6" in out
+
+    def test_opencode_zen_includes_fresh_models(self):
+        """opencode-zen follows the same pattern as opencode-go."""
+        assert "opencode-zen" in _MODELS_DEV_PREFERRED
+        mdev = ["claude-opus-4-7", "kimi-k2.6", "glm-5.1"]
+        with patch("agent.models_dev.list_agentic_models", return_value=mdev):
+            out = provider_model_ids("opencode-zen")
+        assert "claude-opus-4-7" in out
+        assert "kimi-k2.6" in out
+
+
+class TestOpenRouterAndNousUnchanged:
+    """Per Teknium: openrouter and nous are NEVER merged with models.dev."""
+
+    def test_openrouter_not_in_preferred_set(self):
+        assert "openrouter" not in _MODELS_DEV_PREFERRED
+
+    def test_nous_not_in_preferred_set(self):
+        assert "nous" not in _MODELS_DEV_PREFERRED
+
+    def test_openrouter_does_not_call_merge(self):
+        """openrouter takes its own live path — merge helper must NOT run."""
+        with patch(
+            "hermes_cli.models._merge_with_models_dev",
+            side_effect=AssertionError("merge should not be called for openrouter"),
+        ):
+            # Even if model_ids() fails for some other reason, we just care
+            # that the merge path isn't invoked.
+            try:
+                provider_model_ids("openrouter")
+            except AssertionError:
+                raise
+            except Exception:
+                pass  # model_ids() may fail in the hermetic test env — that's fine.