Implements the add command to create new decision nodes.

Usage: deciduex add <type> <title> [options]

Options: -c, --confidence <n> Confidence level 0-100 -p, --prompt <text> User prompt text --prompt-stdin Read prompt from stdin -f, --files <list> Comma-separated file list -b, --branch <name> Git branch name --no-branch Don't auto-detect branch --commit <hash> Git commit hash (use HEAD for current) --date <date> Backdate node (YYYY-MM-DD or RFC3339) -d, --description <text> Node description