fix: widen Context.log level to full LoggingLevel

The MCP spec defines 8 RFC-5424 syslog severity levels (debug, info,
notice, warning, error, critical, alert, emergency). Context.log
previously only accepted 4 of them via a local Literal, even though
ServerSession.send_log_message and LoggingMessageNotificationParams
already accept the full LoggingLevel type.

The debug/info/warning/error convenience methods are unchanged; they
cover the common cases. Callers needing the other levels go through
ctx.log() directly.

Github-Issue: #397

Author: maxisbey

src/mcp/server/mcpserver/context.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from collections.abc import Iterable
-from typing import TYPE_CHECKING, Any, Generic, Literal
+from typing import TYPE_CHECKING, Any, Generic
 
 from pydantic import AnyUrl, BaseModel
 
@@ -14,6 +14,7 @@
     elicit_with_validation,
 )
 from mcp.server.lowlevel.helper_types import ReadResourceContents
+from mcp.types import LoggingLevel
 
 if TYPE_CHECKING:
     from mcp.server.mcpserver.server import MCPServer
@@ -186,15 +187,16 @@ async def elicit_url(
 
     async def log(
         self,
-        level: Literal["debug", "info", "warning", "error"],
+        level: LoggingLevel,
         data: Any,
         *,
         logger_name: str | None = None,
     ) -> None:
         """Send a log message to the client.
 
         Args:
-            level: Log level (debug, info, warning, error)
+            level: Log level (debug, info, notice, warning, error, critical,
+                alert, emergency)
             data: The data to be logged. Any JSON serializable type is allowed
                 (string, dict, list, number, bool, etc.) per the MCP specification.
             logger_name: Optional logger name