[Feature Request]: Top Operations tab for QUERY RESULTS

### Feature Description

With ADS retirement, it would be very useful to port the Top Operations tab over to VS Code to facilitate analysis of complex, multi-node execution plans.

### Problem and Motivation

With the less-than-intuitive "Find Node" feature currently in the mssql extension (side note: I think it needs a fair amount of debugging), it's nearly impossible to quickly zero-in on the most significant nodes on a large execution plan. Providing a Top Operations tab will allow immediate access to the most expensive nodes.

### Related Area

- [ ] Connection dialog
- [x] Query results panel
- [ ] Query editor
- [ ] Object Explorer
- [ ] Table Designer
- [ ] Schema Compare
- [ ] Schema Designer
- [ ] Local container
- [ ] GitHub Copilot integration
- [x] Query Plan Visualizer
- [ ] Other (please describe below)

### If you selected "Other", please describe the area

_No response_

### Confirmation

- [x] I have searched existing feature requests and couldn't find a match
- [ ] I want to help implement this feature

Start by reviewing the mssql extension's Query Results panel and Query Plan Visualizer, then compare the retired ADS Top Operations tab with the existing Find Node behavior. Done means a VS Code Top Operations tab that helps users quickly identify the most expensive nodes in complex, multi-node execution plans.

Written by the indexing model from the issue text.