feat(xiaomi): add Xiaomi MiMo as first-class provider

Cherry-picked from PR #7702 by kshitijk4poor.

Adds Xiaomi MiMo as a direct provider (XIAOMI_API_KEY) with models:
- mimo-v2-pro (1M context), mimo-v2-omni (256K, multimodal), mimo-v2-flash (256K, cheapest)

Standard OpenAI-compatible provider checklist: auth.py, config.py, models.py,
main.py, providers.py, doctor.py, model_normalize.py, model_metadata.py,
models_dev.py, auxiliary_client.py, .env.example, cli-config.yaml.example.

Follow-up: vision tasks use mimo-v2-omni (multimodal) instead of the user's
main model. Non-vision aux uses the user's selected model. Added
_PROVIDER_VISION_MODELS dict for provider-specific vision model overrides.
On failure, falls back to aggregators (gemini flash) via existing fallback chain.

Corrects pre-existing context lengths: mimo-v2-pro 1048576→1000000,
mimo-v2-omni 1048576→256000, adds mimo-v2-flash 256000.

36 tests covering registry, aliases, auto-detect, credentials, models.dev,
normalization, URL mapping, providers module, doctor, aux client, vision
model override, and agent init.

agent/auxiliary_client.py

@@ -109,6 +109,15 @@ _API_KEY_PROVIDER_AUX_MODELS: Dict[str, str] = {
     "opencode-zen": "gemini-3-flash",
     "opencode-go": "glm-5",
     "kilocode": "google/gemini-3-flash-preview",
+    "xiaomi": "mimo-v2-flash",
+}
+
+# Vision-specific model overrides for direct providers.
+# When the user's main provider has a dedicated vision/multimodal model that
+# differs from their main chat model, map it here.  The vision auto-detect
+# "exotic provider" branch checks this before falling back to the main model.
+_PROVIDER_VISION_MODELS: Dict[str, str] = {
+    "xiaomi": "mimo-v2-omni",
 }
 
 # OpenRouter app attribution headers
@@ -1687,16 +1696,18 @@ def resolve_vision_provider_client(
                 if sync_client is not None:
                     return _finalize(main_provider, sync_client, default_model)
             else:
-                # Exotic provider (DeepSeek, Alibaba, named custom, etc.)
+                # Exotic provider (DeepSeek, Alibaba, Xiaomi, named custom, etc.)
+                # Use provider-specific vision model if available, otherwise main model.
+                vision_model = _PROVIDER_VISION_MODELS.get(main_provider, main_model)
                 rpc_client, rpc_model = resolve_provider_client(
-                    main_provider, main_model)
+                    main_provider, vision_model)
                 if rpc_client is not None:
                     logger.info(
                         "Vision auto-detect: using active provider %s (%s)",
-                        main_provider, rpc_model or main_model,
+                        main_provider, rpc_model or vision_model,
                     )
                     return _finalize(
-                        main_provider, rpc_client, rpc_model or main_model)
+                        main_provider, rpc_client, rpc_model or vision_model)
 
         # Fall back through aggregators.
         for candidate in _VISION_AUTO_PROVIDER_ORDER:

agent/model_metadata.py

@@ -27,12 +27,14 @@ _PROVIDER_PREFIXES: frozenset[str] = frozenset({
     "gemini", "zai", "kimi-coding", "minimax", "minimax-cn", "anthropic", "deepseek",
     "opencode-zen", "opencode-go", "ai-gateway", "kilocode", "alibaba",
     "qwen-oauth",
+    "xiaomi",
     "custom", "local",
     # Common aliases
     "google", "google-gemini", "google-ai-studio",
     "glm", "z-ai", "z.ai", "zhipu", "github", "github-copilot",
     "github-models", "kimi", "moonshot", "claude", "deep-seek",
     "opencode", "zen", "go", "vercel", "kilo", "dashscope", "aliyun", "qwen",
+    "mimo", "xiaomi-mimo",
     "qwen-portal",
 })
 
@@ -150,8 +152,9 @@ DEFAULT_CONTEXT_LENGTHS = {
     "moonshotai/Kimi-K2-Thinking": 262144,
     "MiniMaxAI/MiniMax-M2.5": 204800,
     "XiaomiMiMo/MiMo-V2-Flash": 32768,
-    "mimo-v2-pro": 1048576,
-    "mimo-v2-omni": 1048576,
+    "mimo-v2-pro": 1000000,
+    "mimo-v2-omni": 256000,
+    "mimo-v2-flash": 256000,
     "zai-org/GLM-5": 202752,
 }
 
@@ -211,6 +214,8 @@ _URL_TO_PROVIDER: Dict[str, str] = {
     "api.fireworks.ai": "fireworks",
     "opencode.ai": "opencode-go",
     "api.x.ai": "xai",
+    "api.xiaomimimo.com": "xiaomi",
+    "xiaomimimo.com": "xiaomi",
 }
 
 

agent/models_dev.py

@@ -161,6 +161,7 @@ PROVIDER_TO_MODELS_DEV: Dict[str, str] = {
     "gemini": "google",
     "google": "google",
     "xai": "xai",
+    "xiaomi": "xiaomi",
     "nvidia": "nvidia",
     "groq": "groq",
     "mistral": "mistral",