CI for Sandbox: Use Gemma-3 4B

Author: ariya

.github/workflows/sandbox.yml

@@ -11,7 +11,7 @@ jobs:
       fail-fast: false
       matrix:
         model:
-          - meta-llama/llama-3.2-3b-instruct             # $0.0200/$0.0200 [ 128K]
+          - google/gemma-3-4b-it                         # $0.0200/$0.0400 [ 128K]
     steps:
       - uses: actions/checkout@v4
 
@@ -34,7 +34,7 @@ jobs:
       fail-fast: false
       matrix:
         model:
-          - meta-llama/llama-3.2-3b-instruct             # $0.0200/$0.0200 [  16K]
+          - google/gemma-3-4b-it                         # $0.0200/$0.0400 [ 128K]
     steps:
       - uses: actions/checkout@v4
       - run: ./chat-llm.js tests/en/high-school-stem.txt
@@ -50,7 +50,7 @@ jobs:
       fail-fast: false
       matrix:
         model:
-          - meta-llama/llama-3.2-3b-instruct             # $0.0200/$0.0200 [  16K]
+          - google/gemma-3-4b-it                         # $0.0200/$0.0400 [ 128K]
     steps:
       - uses: actions/checkout@v4
       - run: ./chat-llm.js tests/en/general-knowledge.txt