feat: Proxy and Tor support

[Snider]

Summary

Route requests through proxies or Tor for privacy/access.

Use Case

• Some sites block datacenter IPs
• Privacy when archiving
• Access geo-restricted content

Commands

# HTTP proxy
borg collect website https://example.com --proxy http://proxy:8080

# SOCKS5 proxy
borg collect website https://example.com --proxy socks5://proxy:1080

# Tor (assumes Tor running on 9050)
borg collect website https://example.com --tor

# Rotate proxies from list
borg collect website https://example.com --proxy-list proxies.txt

Proxy List Format

# proxies.txt
http://proxy1:8080
http://proxy2:8080
socks5://proxy3:1080

Rotation Strategies

Strategy	Description
round-robin	Cycle through list
random	Random selection
least-used	Track usage counts
on-error	Switch on failure

Configuration

proxy:
  url: socks5://localhost:9050
  # or
  list: proxies.txt
  rotation: round-robin
  
  auth:
    username: user
    password: pass

Tor Integration

# Auto-start Tor
borg collect website https://example.com --tor --tor-start

# New identity per domain
borg collect website https://example.com --tor --tor-new-identity

Acceptance Criteria

• HTTP/HTTPS proxy support
• SOCKS5 proxy support
• Proxy authentication
• Proxy list with rotation
• Tor integration

[google-labs-jules]

Jules is on it. When finished, you will see another comment and be able to review a PR.

[google-labs-jules]

Ready for a review! A PR has been created.