fix(picker): keep flat-namespace reseller first-party models in desktop picker

OpenCode Go (and OpenCode Zen) showed only a subset of the models they
serve in the desktop/CLI model picker — e.g. opencode-go rendered 13 of
19, silently dropping minimax-m3/m2.7/m2.5, glm-5/5.1, deepseek-v4-flash.

Root cause: the picker dedup in build_models_payload strips any model
from an aggregator row that overlaps a user-defined provider's catalog
(so a local proxy isn't shadowed by OpenRouter). It gated on
is_aggregator(), which is True for opencode-go/zen because their flat
/v1/models returns bare IDs the model-switch resolver searches. But
those are flat-namespace RESELLERS, not routing aggregators — every
model they list is first-party, so deduping them against a user proxy
that happens to serve a same-named model guts their own catalog.

Fix: add is_routing_aggregator() (True only for true routers like
OpenRouter and custom:* proxies; False for opencode-go/zen) and gate the
picker dedup on it. is_aggregator() is unchanged so model-switch flat
catalog resolution keeps working. Both desktop entry points
(model.options JSON-RPC and /api/model/options REST) and hermes model
share build_models_payload, so all surfaces get the full list.

Fixes #47077

tests/hermes_cli/test_inventory.py

@@ -639,6 +639,46 @@ def test_aggregator_dedup_does_not_empty_user_defined_custom_provider():
     assert or_row["total_models"] == 1
 
 
+def test_flat_namespace_reseller_keeps_first_party_models_overlapping_user_proxy():
+    """opencode-go / opencode-zen are flagged ``is_aggregator=True`` (their
+    flat ``/v1/models`` returns bare IDs the model-switch resolver searches),
+    but they are NOT routing aggregators — every model they list is a
+    first-party model under the user's subscription. When a user also runs a
+    custom proxy that happens to serve a same-named model, the picker dedup
+    must NOT strip the reseller's own catalog. Regression for #47077, where
+    opencode-go showed only 13 of 19 models because minimax-m3/m2.7/m2.5,
+    glm-5/5.1, and deepseek-v4-flash were deduped against an overlapping
+    custom provider.
+    """
+    rows = [
+        _user_provider_row("custom:my-proxy", [
+            "minimax-m3", "minimax-m2.7", "glm-5", "deepseek-v4-flash",
+        ]),
+        _aggregator_row("opencode-go", [
+            "kimi-k2.6", "minimax-m3", "minimax-m2.7", "glm-5",
+            "deepseek-v4-flash", "qwen3.7-max",
+        ]),
+        _aggregator_row("openrouter", ["minimax-m3", "anthropic/claude-sonnet-4.6"]),
+    ]
+    ctx = _empty_ctx()
+    with _list_auth_returning(rows):
+        payload = build_models_payload(ctx)
+
+    go_row = next(r for r in payload["providers"] if r["slug"] == "opencode-go")
+    or_row = next(r for r in payload["providers"] if r["slug"] == "openrouter")
+
+    # The reseller keeps ALL of its first-party models — nothing stripped.
+    assert go_row["models"] == [
+        "kimi-k2.6", "minimax-m3", "minimax-m2.7", "glm-5",
+        "deepseek-v4-flash", "qwen3.7-max",
+    ]
+    assert go_row["total_models"] == 6
+
+    # A TRUE routing aggregator is still deduped against the user's models.
+    assert "minimax-m3" not in or_row["models"]
+    assert "anthropic/claude-sonnet-4.6" in or_row["models"]
+
+
 def test_two_custom_providers_with_overlap_both_survive():
     """Two user-defined custom endpoints that happen to expose an
     overlapping model must each keep their full catalog. Neither is the

tests/hermes_cli/test_model_switch_custom_providers.py

@@ -129,6 +129,23 @@ def test_is_aggregator_leaves_unknown_provider_non_aggregator():
     assert providers_mod.is_aggregator("not-a-provider") is False
 
 
+def test_is_routing_aggregator_excludes_flat_namespace_resellers():
+    """opencode-go / opencode-zen stay ``is_aggregator=True`` (model-switch
+    relies on it to search their flat bare-name catalog), but they are NOT
+    routing aggregators — their models are first-party, so the picker dedup
+    must not strip them. (#47077)"""
+    # Still aggregators for model-switch flat-catalog resolution.
+    assert providers_mod.is_aggregator("opencode-go") is True
+    assert providers_mod.is_aggregator("opencode-zen") is True
+    # But NOT routing aggregators for picker-dedup purposes.
+    assert providers_mod.is_routing_aggregator("opencode-go") is False
+    assert providers_mod.is_routing_aggregator("opencode-zen") is False
+    # True routers and custom proxies remain routing aggregators.
+    assert providers_mod.is_routing_aggregator("openrouter") is True
+    assert providers_mod.is_routing_aggregator("custom:litellm") is True
+    assert providers_mod.is_routing_aggregator("not-a-provider") is False
+
+
 def test_switch_model_accepts_explicit_named_custom_provider(monkeypatch):
     """Shared /model switch pipeline should accept --provider for custom_providers."""
     monkeypatch.setattr(