Add centralized text routing policy and premium HF defaults

backend/services/llm_providers/routing_policy.py

@@ -0,0 +1,30 @@
+"""Routing policy for LLM provider aliases and model defaults."""
+
+from typing import Dict, List
+
+
+# Premium text generation defaults
+PREMIUM_DEFAULT_PROVIDER = "huggingface"
+PREMIUM_DEFAULT_MODEL = "openai/gpt-oss-120b:groq"
+
+# SIF low-cost defaults for text generation
+SIF_LOW_COST_MODEL_DEFAULTS: List[str] = [
+    "mistralai/Mistral-7B-Instruct-v0.3:groq",
+]
+
+# Canonical provider aliases for text routing
+PROVIDER_ALIAS_MAPPING: Dict[str, str] = {
+    "gemini": "google",
+    "google": "google",
+    "hf_response_api": "huggingface",
+    "huggingface": "huggingface",
+    "hf": "huggingface",
+    # Text-only alias: route wavespeed GPT_PROVIDER to premium HF text route.
+    "wavespeed": PREMIUM_DEFAULT_PROVIDER,
+}
+
+
+def resolve_text_provider_alias(provider: str) -> str:
+    """Resolve a GPT provider alias into a canonical text provider."""
+    return PROVIDER_ALIAS_MAPPING.get((provider or "").lower(), "")
+