feat: add VS Code extension for browsing and claiming bounties

[Ikalus1988]

Summary

Implements VS Code Extension for Browsing Bounties as described in Bounty T2 #854.

Features

• Sidebar bounty browser: Tree view in VS Code Activity Bar showing open bounties
• Filter by programming language: Filter by Rust, TypeScript, Solidity, Python, Go, etc.
• Filter by tier: T1, T2, T3 bounty tiers
• Filter by status: open, in_review, completed, cancelled, funded
• Filter by reward: Min/max reward amount filters
• Search bounties: Search by title, description, or skills
• Bounty detail webview: Rich webview panel with full bounty info, skills, and metadata
• One-click claim: Claim bounties directly via browser redirect
• Configurable API URL: Connect to any SolFoundry API instance

Files Added

vscode-extension/
├── README.md
├── package.json          # Extension manifest
├── tsconfig.json         # TypeScript config
├── media/icon.svg        # Extension icon
└── src/
    ├── extension.ts       # Main entry, commands, webview
    ├── BountyTreeProvider.ts  # Tree data provider with filters
    ├── api.ts             # API client, filters, constants
    └── types.ts           # Bounty, FilterState types

Acceptance Criteria

• Browse and search bounties in sidebar
• Filter by programming language and reward
• One-click bounty claim functionality

Closes #854

Solana Wallet for Payout

Wallet: (to be provided)