Make public APIs more standard. (#416)

python/sglang/__init__.py

 __version__ = "0.1.14"
 
-from sglang.api import *
+# SGL API Components
+from sglang.api import (
+    Runtime,
+    assistant,
+    assistant_begin,
+    assistant_end,
+    flush_cache,
+    function,
+    gen,
+    gen_int,
+    gen_string,
+    get_server_args,
+    image,
+    select,
+    set_default_backend,
+    system,
+    user,
+    user_begin,
+    user_end,
+)
+
+# SGL Backends
+from sglang.backend.anthropic import Anthropic
+from sglang.backend.openai import OpenAI
+from sglang.backend.runtime_endpoint import RuntimeEndpoint
+from sglang.backend.vertexai import VertexAI
+
+# Global Configurations
 from sglang.global_config import global_config
+
+# public APIs management
+__all__ = [
+    "global_config",
+    "Anthropic",
+    "OpenAI",
+    "RuntimeEndpoint",
+    "VertexAI",
+    "function",
+    "Runtime",
+    "set_default_backend",
+    "flush_cache",
+    "get_server_args",
+    "gen",
+    "gen_int",
+    "gen_string",
+    "image",
+    "select",
+    "system",
+    "user",
+    "assistant",
+    "user_begin",
+    "user_end",
+    "assistant_begin",
+    "assistant_end",
+]

python/sglang/api.py

-"""Public API"""
+"""Some Public API Definitions"""
 
 import re
 from typing import Callable, List, Optional, Union
 
-from sglang.backend.anthropic import Anthropic
 from sglang.backend.base_backend import BaseBackend
-from sglang.backend.openai import OpenAI
-from sglang.backend.runtime_endpoint import RuntimeEndpoint
-from sglang.backend.vertexai import VertexAI
 from sglang.global_config import global_config
 from sglang.lang.ir import (
     SglExpr,