Add optional CommanderBracket.app integration for bracket estimation

[Madwand99]

This adds an optional CommanderBracket.app integration for richer Commander bracket estimates while keeping Forge’s local bracket calculation as the default fallback.

Key changes:

• Adds a new Advanced preference, default off: “Use CommanderBracket.app for bracket calculations”.
• Adds a CommanderBracket service/API client with:
  • public CommanderBracket.app endpoint support
  • Forge/x.y User-Agent
  • single-worker rate limiting
  • request de-duplication and high-priority promotion
  • session caching and failure cooldowns
• Stores API bracket metadata directly in deck files:
  • DeckHash=(sha256)
  • CommanderBracket=(1-5)
• Uses saved/session API brackets in the deck browser and match tooltip when available.
• Keeps local Forge bracket calculation available when the API is disabled, unavailable, or still pending.
• Adds clickable “Powered by Commander Bracket” attribution.
• Updates bracket detail panels to refresh asynchronously when high-priority API details return.
• Adds localized UI strings for all available Forge languages.
• Adds a small shared JsonUtil for simple JSON parsing/escaping used by the API integration.

Thanks to Codex for help with code and keith@commanderbracket.app for help with API access!