feat: package as a Claude Code plugin with a deterministic quality gate

Workflows move to skills/<name>/SKILL.md so the repo installs as a plugin.
scripts/quality-gate runs only the checks of the requested tier on the diff
and reports missing tools as unverified instead of passing them. Hooks block
stopping on a failed or stale gate, guard destructive shell commands and
format edited files with the project's own formatter.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

scripts/hooks/post_edit.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+"""PostToolUse: formats the edited file with the formatter the project already uses. Never fails the edit.
+
+Claude Code: reads tool_input.file_path from the hook JSON on stdin.
+opencode:    `post_edit.py --file <path>`.
+"""
+import json, os, shutil, subprocess, sys
+
+PRETTIER_EXT = {".js", ".jsx", ".ts", ".tsx", ".mjs", ".cjs", ".json", ".css", ".scss", ".html", ".vue", ".svelte", ".md", ".yaml", ".yml"}
+
+
+def project_root(path):
+    d = os.path.dirname(os.path.abspath(path))
+    while d != os.path.dirname(d):
+        if any(os.path.exists(os.path.join(d, m)) for m in ("package.json", "pyproject.toml", "go.mod", "Cargo.toml", ".git")):
+            return d
+        d = os.path.dirname(d)
+    return None
+
+
+def uses_ruff(root):
+    if os.path.exists(os.path.join(root, "ruff.toml")) or os.path.exists(os.path.join(root, ".ruff.toml")):
+        return True
+    pyproject = os.path.join(root, "pyproject.toml")
+    return os.path.exists(pyproject) and "[tool.ruff" in open(pyproject).read()
+
+
+def formatter(path, root):
+    ext = os.path.splitext(path)[1].lower()
+    prettier = os.path.join(root, "node_modules", ".bin", "prettier")
+    if ext in PRETTIER_EXT and os.path.exists(prettier):
+        return [prettier, "--write", "--log-level", "warn", path]
+    if ext == ".py" and shutil.which("ruff") and uses_ruff(root):
+        return ["ruff", "format", "--quiet", path]
+    if ext == ".go" and shutil.which("gofmt"):
+        return ["gofmt", "-w", path]
+    if ext == ".rs" and shutil.which("rustfmt"):
+        return ["rustfmt", path]
+    return None
+
+
+def main():
+    if len(sys.argv) > 2 and sys.argv[1] == "--file":
+        path = sys.argv[2]
+    else:
+        path = json.load(sys.stdin).get("tool_input", {}).get("file_path", "")
+    root = project_root(path) if path and os.path.isfile(path) else None
+    cmd = formatter(path, root) if root else None
+    if cmd:
+        try:
+            subprocess.run(cmd, cwd=root, capture_output=True, timeout=30)
+        except (subprocess.TimeoutExpired, OSError):
+            pass
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())