feat: add Xiaomi MiMo v2.5-pro and v2.5 model support (#14635)

## Merged

Adds MiMo v2.5-pro and v2.5 support to Xiaomi native provider, OpenCode Go, and setup wizard.

### Changes
- Context lengths: added v2.5-pro (1M) and v2.5 (1M), corrected existing MiMo entries to exact values (262144)
- Provider lists: xiaomi, opencode-go, setup wizard
- Vision: upgraded from mimo-v2-omni to mimo-v2.5 (omnimodal)
- Config description updated for XIAOMI_API_KEY
- Tests updated for new vision model preference

### Verification
- 4322 tests passed, 0 new regressions
- Live API tested on Xiaomi portal: basic, reasoning, tool calling, multi-tool, file ops, system prompt, vision — all pass
- Self-review found and fixed 2 issues (redundant vision check, stale HuggingFace context length)

tests/agent/test_auxiliary_main_first.py

@@ -245,7 +245,7 @@ class TestResolveVisionMainFirst:
         assert model == "xiaomi/mimo-v2-omni"
 
     def test_exotic_provider_with_vision_override_preserved(self):
-        """xiaomi → mimo-v2-omni override still wins over main_model."""
+        """xiaomi → mimo-v2.5 override still wins over main_model."""
         with patch(
             "agent.auxiliary_client._read_main_provider", return_value="xiaomi",
         ), patch(
@@ -257,15 +257,15 @@ class TestResolveVisionMainFirst:
             "agent.auxiliary_client._resolve_task_provider_model",
             return_value=("auto", None, None, None, None),
         ):
-            mock_resolve.return_value = (MagicMock(), "mimo-v2-omni")
+            mock_resolve.return_value = (MagicMock(), "mimo-v2.5")
 
             from agent.auxiliary_client import resolve_vision_provider_client
 
             provider, client, model = resolve_vision_provider_client()
 
         assert provider == "xiaomi"
-        # Should use mimo-v2-omni (vision override), not mimo-v2-pro (text main)
-        assert mock_resolve.call_args.args[1] == "mimo-v2-omni"
+        # Should use mimo-v2.5 (vision override), not mimo-v2-pro (text main)
+        assert mock_resolve.call_args.args[1] == "mimo-v2.5"
 
     def test_main_unavailable_vision_falls_through_to_aggregators(self):
         """Main provider fails → fall back to OpenRouter/Nous strict backends."""

tests/hermes_cli/test_xiaomi_provider.py

@@ -287,10 +287,10 @@ class TestXiaomiAuxiliary:
         assert "xiaomi" not in _API_KEY_PROVIDER_AUX_MODELS
 
     def test_vision_model_override(self):
-        """Xiaomi vision tasks should use mimo-v2-omni (multimodal), not the main model."""
+        """Xiaomi vision tasks should use mimo-v2.5 (multimodal), not the main model."""
         from agent.auxiliary_client import _PROVIDER_VISION_MODELS
         assert "xiaomi" in _PROVIDER_VISION_MODELS
-        assert _PROVIDER_VISION_MODELS["xiaomi"] == "mimo-v2-omni"
+        assert _PROVIDER_VISION_MODELS["xiaomi"] == "mimo-v2.5"
 
 
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