fix: prioritize oldest uncompleted deployment for head selection

[Vishakha7-Kumari]

What this PR does / Why we need it

This PR fixes a bug in the synchronization logic of the pipedv1 deployment store.

Currently, sync builds the headDeployments map by iterating sequentially over pending, planned, and running deployments. As a result, running deployments (or newer deployments processed later in the sequence) always overwrite other uncompleted ones. This contradicts the contract defined in ListAppHeadDeployments():

"Head deployment is same with the oldest uncompleted one" (Issue #6780).

To fix this, we introduce an updateHead helper which compares the CreatedAt timestamps of the deployments. It only populates or updates headDeployments if a candidate deployment has a smaller CreatedAt timestamp (i.e. is older), guaranteeing that the oldest uncompleted deployment is always selected as the head.

Changes

• Store Logic: Updated store.go to select the oldest uncompleted deployment by comparing CreatedAt.
• Tests: Added test cases in store_test.go covering scenarios where either the running or the pending deployment is the oldest.

Fixes #6780

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[Copilot]

Pull request overview

This PR fixes pipedv1’s deployment-store head selection to align with the ListAppHeadDeployments() contract (“head = oldest uncompleted deployment”) by selecting per-application heads based on CreatedAt rather than overwrite order.

Changes:

• Update sync() head selection to keep the oldest deployment per application by comparing CreatedAt.
• Add unit tests covering cases where the running vs pending deployment is the oldest for the same application.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
pkg/app/pipedv1/apistore/deploymentstore/store.go	Adjusts head-deployment selection logic to prefer the oldest uncompleted deployment using CreatedAt.
pkg/app/pipedv1/apistore/deploymentstore/store_test.go	Adds test coverage for selecting the oldest head deployment across mixed pending/running states.

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