fix: Use OPENAI_API_KEY secret in CI instead of fake key

Replace hardcoded 'fake-key-for-testing' with GitHub Actions secret
to enable proper LLM and embedding functionality in CI tests.

🤖 Generated with Claude Code

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/mcp-server-tests.yml

@@ -194,7 +194,7 @@ jobs:
           NEO4J_URI: bolt://localhost:7687
           NEO4J_USER: neo4j
           NEO4J_PASSWORD: testpassword
-          OPENAI_API_KEY: fake-key-for-testing
+          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
           GRAPHITI_GROUP_ID: ci-test-group
 
       - name: Wait for FalkorDB to be ready
@@ -268,7 +268,7 @@ jobs:
           FALKORDB_URI: redis://localhost:6379
           FALKORDB_PASSWORD: ""
           FALKORDB_DATABASE: default_db
-          OPENAI_API_KEY: fake-key-for-testing
+          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
           GRAPHITI_GROUP_ID: ci-falkor-test-group
 
       - name: Test server startup with Neo4j
@@ -295,7 +295,7 @@ jobs:
           NEO4J_URI: bolt://localhost:7687
           NEO4J_USER: neo4j
           NEO4J_PASSWORD: testpassword
-          OPENAI_API_KEY: fake-key-for-testing
+          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
 
       - name: Test server startup with FalkorDB
         run: |
@@ -321,4 +321,4 @@ jobs:
           FALKORDB_URI: redis://localhost:6379
           FALKORDB_PASSWORD: ""
           FALKORDB_DATABASE: default_db
-          OPENAI_API_KEY: fake-key-for-testing
+          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}