Build VS Code Extension: NEAR Account Lookup

Description

## Overview
Create a VS Code extension that provides quick account lookups - hover over any NEAR account ID to see balance and details.

## Why This Matters
Account lookups are frequent during development. Quick inline info improves developer experience.

## Technical Requirements
- Detect NEAR account IDs
- Show balance on hover
- Display recent activity
- Link to explorer
- Network switching

## Deliverables
1. VS Code extension
2. Hover details
3. Activity summary
4. Documentation