Support ~/.config/claude for CLAUDE.md and settings

Feature Request

Claude Code should check ~/.config/claude/ in addition to ~/.claude/ for user configuration files (CLAUDE.md, settings, etc.).

Rationale

The ~/.config/ directory follows the XDG Base Directory Specification, which is the modern standard for user configuration on Linux and increasingly adopted on macOS.

Many users prefer to keep their home directory clean and organize configs under ~/.config/.

Suggested Behavior

• Check both ~/.claude/ and ~/.config/claude/
• Respect $XDG_CONFIG_HOME if set (defaults to ~/.config)
• Document the precedence if both locations exist