Distinguish and sort transitive packages in the Project View

[Copilot]

The Project View rendered direct and transitive packages identically, while the Environment View distinguishes them (icon, label, tooltip) and sorts direct-first. This made the two views inconsistent.

Changes

• treeViewItems.ts (ProjectPackage) — mirror PackageTreeItem: list-tree icon for transitive (vs package), (transitive) description prefix, and the explanatory dependency tooltip. Package-provided iconPath still takes precedence.
• projectView.ts — sort packages direct-first using the same comparator as the Environment View before mapping to tree items.
• Robustness — fall back to '' when both version and description are absent, avoiding a stray undefined in the label; applied to both views.
• Tests — add a ProjectPackage suite covering direct vs. transitive rendering, icon override, and the empty-description case.

// projectView.ts — direct packages first, then transitive
return packages
    .sort((a, b) => (a.isTransitive === b.isTransitive ? 0 : a.isTransitive ? 1 : -1))
    .map((p) => new ProjectPackage(environmentItem, p, pkgManager));

Note: the description/tooltip/icon logic is intentionally duplicated across ProjectPackage and PackageTreeItem to keep the two views in lockstep; a shared helper is a reasonable follow-up if further divergence is a concern.