Fix negative cooling coil capacity warning when system cooling load available

[joseph-robertson]

Pull request overview

• Fixes Cooling Design Day name not populated by the time VariableSpeedCoil sizing happens. #11250
• Basically breaks the existing negative cooling coil capacity CoolCapAtPeak < 0 warning into 2 separate warnings (per suggestion):
  • when there is no system cooling load (sensible/total capacity is zero, and no cooling design day is assigned/reported) <-- update the existing unit test
  • when there is system cooling load (rare, but technically possible; sensible/total capacity greater than zero, and cooling design day is assigned/reported) <-- add a new unit test

Description of the purpose of this PR

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[joseph-robertson]

This is increased from 31.5 relative the VSCoilUnitary_NoNegativeCapacity test.

[joseph-robertson]

This is increased from 32.222 relative the VSCoilUnitary_NoNegativeCapacity test.

[Copilot]

Pull request overview

This PR addresses issue #11250 by refining the warning emitted when a VariableSpeed DX cooling coil would yield a negative sizing capacity, distinguishing between cases where a system cooling design day/load is available vs not available. It also ensures the cooling design day index is propagated into final system sizing data, and updates unit tests to cover both scenarios.

Changes:

• Split the negative-capacity sizing warning into two distinct messages depending on whether cooling sizing context (design day/load) is available.
• Record CoolDDNum during system sizing peak selection and copy it into FinalSysSizing for downstream consumers (eg, coil sizing diagnostics).
• Update the existing unit test and add a new unit test to validate both warning paths.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 5 comments.

File	Description
tst/EnergyPlus/unit/UnitarySystem.unit.cc	Updates existing test expectations for the new warning text and adds a new test case covering the “cooling load available” path.
src/EnergyPlus/VariableSpeedCoils.cc	Updates the warning message logic when calculated peak cooling capacity is negative during sizing.
src/EnergyPlus/SimAirServingZones.cc	Propagates cooling design day index (CoolDDNum) into calculated and final system sizing data used by downstream sizing/reporting.

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