refactor: convert rows to signal input

[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)

rows is a decorator input.

What is the new behavior?

rows is a signal input.

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

• Yes, but message is contained in another commit
• No

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

Other information:

Turns _internalRows into a signal. There is more potential once groupedRows is a signal as well.

[spike-rabbit]

@fh1ch the sorting now behaves slightly differently. Before:

// The same array will be sorted each time the users sorts.
// Assuming the are values, that have the same sort order.
// Then we have different results based on the order in which a user sorts columns
[...].sort().sort().sort()

After

// The original array is copied.
// We always get the same result.
// Independent of the order in which a user sorts.
const rows = [...];
rows.slice().sort();
rows.slice().sort();
rows.slice().sort();

[Copilot]

Pull Request Overview

This PR refactors the rows input from a decorator-based input with getter/setter to an Angular signal input, and converts _internalRows from a plain array to a computed signal. This is part of a broader migration to Angular's signals-based reactivity system.

Key Changes

• Converted rows from @Input() decorator to input<>() signal
• Converted _internalRows from a mutable array to a computed() signal that handles sorting, tree grouping, and ghost loading
• Removed the _rows backing field and translateColumns() method as they're no longer needed
• Updated all references to rows and _internalRows to call them as functions

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
projects/ngx-datatable/src/lib/components/datatable.component.ts	Refactored rows to signal input, converted _internalRows to computed signal with internal logic for sorting and tree grouping, removed obsolete helper methods and effects
projects/ngx-datatable/src/lib/components/datatable.component.spec.ts	Updated test expectations to reflect changes in sort behavior (appears to be regression)
projects/ngx-datatable/src/lib/components/datatable.component.html	Updated template bindings to call _internalRows() as a function instead of accessing it as a property

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[fh1ch]

@spike-rabbit nice one, thanks a lot 🙇

LGTM 👍