Add config files for Claude Code

[boomzero]

What does this PR aim to accomplish?:

Add config files for Claude Code

How does this PR accomplish the above?:

Add config files for Claude Code

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Summary by cubic

Add Claude Code configuration to improve code navigation for the large XMOJ.user.js and provide clear repo guidance for contributors. Also cleans up stray macOS metadata files.

• New Features

  • Added CLAUDE.md with project overview, branch/workflow rules, version automation, and testing notes.
  • Added .claude/agents/xmoj-code-navigator.md agent to efficiently locate and extract code snippets from XMOJ.user.js.

• Refactors

  • Removed accidental ._ files (macOS resource forks).

^{Written for commit 01de30b. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 6 files