Build VS Code Extension: NEAR Smart Contract Developer Kit

Description

## Overview
Create a comprehensive VS Code extension for NEAR smart contract development - syntax highlighting, snippets, inline documentation, and deployment.

## Why This Matters
VS Code is the most popular IDE. A great extension makes NEAR development a first-class experience.

## Technical Requirements

### Features

**1. Syntax & Highlighting**
- NEAR SDK macro highlighting (`#[near_bindgen]`, `#[payable]`, etc.)
- JSON schema validation for near-sdk types
- Error highlighting for common mistakes

**2. Snippets (20+)**
```rust
// Type "nearcontract" + Tab
#[near_bindgen]
#[derive(BorshDeserialize, BorshSerialize)]
pub struct Contract {
// fields
}

#[near_bindgen]
impl Contract {
#[init]
pub fn new() -> Self {
// ...
}
}
```

**3. IntelliSense**
- Autocomplete for NEAR SDK methods
- Parameter hints for contract calls
- Documentation on hover

**4. Commands**
- `NEAR: Build Contract` - Build with cargo
- `NEAR: Deploy to Testnet` - One-click deploy
- `NEAR: Run Tests` - Run near-workspaces tests
- `NEAR: Open Explorer` - View account in explorer

**5. Sidebar**
- Account info and balance
- Deployed contracts
- Transaction history
- Quick actions

### Technical Implementation
- Language Server Protocol for IntelliSense
- Webview for sidebar
- Credential storage via VS Code SecretStorage
- Configuration for network, accounts

## Deliverables
1. **VS Code extension** published to Marketplace
2. **20+ snippets** for common patterns
3. **IntelliSense** for NEAR SDK
4. **Commands** for build/deploy/test
5. **Documentation**

## Budget: 12 NEAR