Add support for EMBEDDING_API_KEY (#2691)

* feat: support for embedding API key

* feat: encrypt and decrypt embedding API key

* test: add unit tests for EmbeddingClient authorization header behavior

routes/embedding_routes.py

@@ -258,7 +258,7 @@ def setup_embedding_routes():
         }
 
     @router.post("/endpoint")
-    def set_endpoint(url: str = Form(...), model: str = Form("")):
+    def set_endpoint(url: str = Form(...), model: str = Form(""), api_key: str = Form("")):
         """Save a custom embedding endpoint URL."""
         url = url.strip()
         if not url:
@@ -282,6 +282,7 @@ def setup_embedding_routes():
             resp = httpx.post(
                 url,
                 json={"input": ["test"], "model": model or "test"},
+                headers={"Authorization": f"Bearer {api_key}"} if api_key else {},
                 timeout=10,
             )
             resp.raise_for_status()
@@ -292,10 +293,16 @@ def setup_embedding_routes():
         data = {"url": url}
         if model:
             data["model"] = model
+        if api_key:
+            from src.secret_storage import encrypt
+            data["api_key"] = encrypt(api_key)
+
         _save_custom_endpoint(data)
         os.environ["EMBEDDING_URL"] = url
         if model:
             os.environ["EMBEDDING_MODEL"] = model
+        if api_key:
+            os.environ["EMBEDDING_API_KEY"] = api_key
 
         # Reset the RAG singleton so it picks up the new endpoint
         import src.rag_singleton as _rs
@@ -329,6 +336,7 @@ def setup_embedding_routes():
         # Remove from environment
         os.environ.pop("EMBEDDING_URL", None)
         os.environ.pop("EMBEDDING_MODEL", None)
+        os.environ.pop("EMBEDDING_API_KEY", None)
 
         # Reset the RAG singleton so it falls back to fastembed
         import src.rag_singleton as _rs