feat: grafana loki backend

[EvertonSA]

loki remote logging, partially resolves #64639

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• For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
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[Copilot]

Pull request overview

Adds a new Grafana provider integration to support Grafana Loki as a remote logging backend in Airflow, including packaging/workspace registration.

Changes:

• Registers apache-airflow-providers-grafana in the workspace and adds a grafana extra.
• Introduces a Loki remote log IO + task handler implementation to upload/read task logs via Loki’s HTTP API.
• Adds unit tests validating upload cleanup behavior, label cardinality strategy, and generated LogQL.

Reviewed changes

Copilot reviewed 11 out of 14 changed files in this pull request and generated 12 comments.

File	Description
uv.lock	Adds the Grafana provider package to the lock/workspace metadata and updates extras/dependency markers.
pyproject.toml	Registers the new provider, adds grafana extra + mypy paths, and adjusts a couple of provider extra markers.
providers/grafana/src/airflow/providers/grafana/loki/log/loki_task_handler.py	Implements LokiRemoteLogIO and LokiTaskHandler for Loki push/query and Airflow logging integration.
providers/grafana/tests/unit/grafana/loki/log/test_loki_task_handler.py	Adds unit tests for Loki upload and query behavior.

[EvertonSA]

closing in favor of sidecar strategy