Complete TreeExplorer V1→V2 migration (PrimeVue → Reka UI)

## Recommendation

### 🔀 CONSOLIDATE: Complete Tree Component Migration

PrimeVue-based TreeExplorer V1 coexists with the newer Reka UI-based TreeExplorer V2. Both are actively used by different parts of the UI.

## What Was Found

- **V1**: PrimeVue Tree component wrapper
- **V2**: Reka UI-based implementation (newer, aligns with design system direction)
- Both have active consumers
- Per AGENTS.md: "Avoid new usage of PrimeVue components"

## How to Fix

1. Identify remaining V1 consumers
2. Migrate each to use V2
3. Remove V1 implementation

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**Category:** Conflicting Systems | **Priority:** Nice-to-have | **Effort:** Medium
Part of #11022
_Filed by repo-audit skill_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-11081-Complete-TreeExplorer-V1-V2-migration-PrimeVue-Reka-UI-33e6d73d36508182bd8bc2e02da612f2) by [Unito](https://www.unito.io)

Read AGENTS.md, then search the repository for TreeExplorer V1 consumers and the newer V2 entry point. Compare the PrimeVue and Reka UI usages before migrating each remaining consumer; the work is done when consumers use V2 and the V1 implementation can be removed.

Written by the indexing model from the issue text.