fix(header): handle drag end without movement

[spike-rabbit]

What kind of change does this PR introduce? (check one with "x")

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior? (You can also link to an open issue here)

Holding a reorderable column header until dragging starts and releasing it without moving leaves no drag-move event for the orderable directive. Drag end then attempts to destructure an undefined event and breaks subsequent column dragging.

Closes #790

What is the new behavior?

Every drag lifecycle event carries the latest pointer position, including drag end when the pointer never moved. The header handles drag events through normal template bindings and owns reorder target state directly, removing the descendant output subscriptions and the orderable directive. Column movement uses a direct translateX transform and is cleared when dragging ends.

Does this PR introduce a breaking change? (check one with "x")

• Yes
• No

If this PR contains a breaking change, please describe the impact and migration path for existing applications: N/A

Other information:

Note: This is a backport of the original PR #797.

[Copilot]

Pull request overview

This PR fixes a column-reorder drag edge case where releasing after the long-press delay but without any pointer movement could leave downstream drag handlers without a usable event payload, breaking subsequent drags. It does this by ensuring drag lifecycle events always include the latest pointer position and by moving reorder target tracking into the header component (removing the orderable directive).

Changes:

• Extend DatatableDraggableDirective so dragStart/dragEnd emit a DragEvent (including the last known pointer position).
• Remove OrderableDirective and shift reorder target detection + drag translation (translateX) into DataTableHeaderComponent.
• Add/adjust unit tests to cover “drag end without movement” and prevent reorder in that scenario.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
projects/ngx-datatable/src/lib/types/internal.types.ts	Removes internal reorder-target-related types/fields that are no longer used after dropping OrderableDirective.
projects/ngx-datatable/src/lib/directives/orderable.directive.ts	Removes the directive previously responsible for header reorder targeting and drag subscriptions.
projects/ngx-datatable/src/lib/directives/orderable.directive.spec.ts	Removes tests tied specifically to the deleted OrderableDirective.
projects/ngx-datatable/src/lib/directives/draggable.directive.spec.ts	Updates dragEnd typing and adds coverage for drag end without movement including initial pointer position.
projects/ngx-datatable/src/lib/directives/datatable-draggable.directive.ts	Ensures drag lifecycle events emit a consistent DragEvent payload (including on drag end without movement).
projects/ngx-datatable/src/lib/components/header/header.component.ts	Handles drag start/move/end directly via template bindings; computes reorder target via elementsFromPoint; uses translateX for visual movement and resets at end.
projects/ngx-datatable/src/lib/components/header/header.component.spec.ts	Adds coverage to ensure no reorder occurs when drag ends without pointer movement and transform is cleared.

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[fh1ch]

@spike-rabbit all good, thanks a lot 🙇

LGTM 👍