feat(skiff): align CLI with Vercel skills and fix entry symlink

Replace install/uninstall with add/remove, add publish for git ops in
~/.skills, and resolve bin/skiff symlinks so commands work from any cwd.

Co-authored-by: Cursor <cursoragent@cursor.com>

bin/skiff

@@ -1,5 +1,14 @@
 #!/usr/bin/env bash
 set -euo pipefail
-REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+
+# 跟随软链，确保从 ~/.local/bin/skiff 调用时仍能找到仓库根目录
+SCRIPT="${BASH_SOURCE[0]}"
+while [ -L "$SCRIPT" ]; do
+  link_dir="$(cd "$(dirname "$SCRIPT")" && pwd)"
+  SCRIPT="$(readlink "$SCRIPT")"
+  [[ "$SCRIPT" != /* ]] && SCRIPT="$link_dir/$SCRIPT"
+done
+REPO_ROOT="$(cd "$(dirname "$SCRIPT")/.." && pwd)"
+
 export PYTHONPATH="${REPO_ROOT}${PYTHONPATH:+:$PYTHONPATH}"
 exec python3 -m skiff "$@"