fix(#370): add mypy import-untyped ignore for mosaicstack_telemetry

The mosaicstack-telemetry package lacks py.typed marker. Add type
ignore comment consistent with other import sites.

Refs #370

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/coordinator/src/mosaic_telemetry.py

@@ -16,7 +16,7 @@ from __future__ import annotations
 import logging
 from typing import TYPE_CHECKING
 
-from mosaicstack_telemetry import (
+from mosaicstack_telemetry import (  # type: ignore[import-untyped]
     Complexity,
     EventBuilder,
     Harness,