add query domain handler

src/mini_db_mcp/domain/handler/query_handler.py

@@ -0,0 +1,21 @@
+from types import MappingProxyType
+from typing import Mapping
+
+from mini_db_mcp.domain.domain_handler import ToolHandler
+from mini_db_mcp.domain.runtime.query_runtime import QueryRuntime
+
+
+class QueryHandler:
+    domain_name = "query"
+
+    def __init__(self, runtime: QueryRuntime) -> None:
+        self._handlers: Mapping[str, ToolHandler] = MappingProxyType(
+            {"execute_query": runtime.execute_query}
+        )
+
+    @property
+    def handler_names(self) -> frozenset[str]:
+        return frozenset(self._handlers)
+
+    def resolve_handler(self, name: str) -> ToolHandler | None:
+        return self._handlers.get(name)