feat(gateway): update llm-gateway.yaml for free tier

llm-gateway.yaml

@@ -59,45 +59,65 @@ providers:
 
 models:
   # ═══ TIER 1: Free (OpenRouter free models, $0) ═══
-  - name: "deepseek-v3-free"
+  - name: "llama-3.3-70b-free"
     routes:
       - provider: openrouter
-        model: "deepseek/deepseek-v3.2-20251201:free"
+        model: "meta-llama/llama-3.3-70b-instruct:free"
 
-  - name: "gemini-2.5-flash-free"
+  - name: "deepseek-r1-free"
     routes:
       - provider: openrouter
-        model: "google/gemini-2.5-flash:free"
-
-  - name: "gemini-2.0-flash-free"
-    routes:
-      - provider: openrouter
-        model: "google/gemini-2.0-flash-001:free"
+        model: "deepseek/deepseek-r1-0528:free"
 
   - name: "gpt-oss-free"
     routes:
       - provider: openrouter
         model: "openai/gpt-oss-120b:free"
 
-  - name: "gpt-5-nano-free"
+  - name: "gpt-oss-20b-free"
     routes:
       - provider: openrouter
-        model: "openai/gpt-5-nano-2025-08-07:free"
+        model: "openai/gpt-oss-20b:free"
 
-  - name: "grok-4.1-fast-free"
+  - name: "qwen3-coder-free"
     routes:
       - provider: openrouter
-        model: "x-ai/grok-4.1-fast:free"
+        model: "qwen/qwen3-coder:free"
+
+  - name: "qwen3-235b-free"
+    routes:
+      - provider: openrouter
+        model: "qwen/qwen3-235b-a22b-thinking-2507"
+
+  - name: "glm-4.5-air-free"
+    routes:
+      - provider: openrouter
+        model: "z-ai/glm-4.5-air:free"
+
+  - name: "nemotron-nano-free"
+    routes:
+      - provider: openrouter
+        model: "nvidia/nemotron-nano-9b-v2:free"
 
   - name: "trinity-large-free"
     routes:
       - provider: openrouter
         model: "arcee-ai/trinity-large-preview:free"
 
-  - name: "kimi-k2.5-free"
+  - name: "mistral-small-free"
     routes:
       - provider: openrouter
-        model: "moonshotai/kimi-k2.5-0127:free"
+        model: "mistralai/mistral-small-3.1-24b-instruct:free"
+
+  - name: "gemma-3-27b-free"
+    routes:
+      - provider: openrouter
+        model: "google/gemma-3-27b-it:free"
+
+  - name: "step-3.5-flash-free"
+    routes:
+      - provider: openrouter
+        model: "stepfun/step-3.5-flash:free"
 
   # ═══ TIER 2: Low cost (Groq, Cerebras — free tier with rate limits) ═══
   - name: "llama-3.3-70b"