#46 · Add `bounties_open` MCP tool

Context

MCP-aware AI agents (Claude Code, Claude Desktop) should be able to query open bounties. Adds another tool alongside search_community, ask_irregularchat, etc.

Acceptance criteria

• [ ] New tool bounties_open(app?: string, tier?: string) returns up to 25 open bounties
• [ ] Tool description includes link to /bounties page on score.irregulars.io
• [ ] Tool registered in MCP server init

Technical hints

• Calls https://score.irregulars.io/api/bounties (depends on scoreboard JSON endpoint bounty)

--- *Submit a merge request that says Closes #<this issue iid> in the description. On merge to main, the GitLab webhook will auto-award your bounty + the standard merge_pr (40 pts) to your scoreboard account. Email on commit must match your Authentik email.*