UI: Change queued Dag runs color to grey in Calendar

[parkhojeong]

Problem

The Calendar view currently renders queued-only Total Runs cells in green, making them visually
indistinguishable from successful cells

repro.py

from __future__ import annotations

import pendulum

from airflow.sdk import DAG, task

with DAG(
    dag_id="repro",
    start_date=pendulum.datetime(2026, 4, 8, tz="UTC"),
    schedule=None,
) as dag:
    @task
    def noop():
        return "ok"

    noop()

repro

• add repro.py
• breeze start-airflow
• airflowctl dags pause repro
• airflowctl dags trigger --dag-id repro --dag-run-id queued --logical-date "2026-04-08T10:00:00+00:00"

Fix

Update the Calendar color utilities so queued runs use the Planned gray treatment instead of the green

Queued runs are excluded from actual run intensity calculations in total mode. Queued-only cells now render
with the planned color, and cells with both queued and actual runs render as mixed planned/actual colors.

Added focused tests for Calendar run count bounds and color selection across total and failed modes.

Before	After

Closes: #66614

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Was generative AI tooling used to co-author this PR?

• Yes (codex gpt-5.5)