lint: upgrade lint scripts for worktrees

Add a ci/lint.py script to run the linter both locally or inside the CI
(replacing .github/ci-lint-exec.py) which supports running from a
worktree.

Determines whether we are in a worktree, and mounts the real `.git`
directory as a read-only volume if we are.

.github/ci-lint-exec.py

@@ -1,55 +0,0 @@
-#!/usr/bin/env python3
-# Copyright (c) The Bitcoin Core developers
-# Distributed under the MIT software license, see the accompanying
-# file COPYING or https://opensource.org/license/mit.
-
-import os
-import shlex
-import subprocess
-import sys
-import time
-
-
-def run(cmd, **kwargs):
-    print("+ " + shlex.join(cmd), flush=True)
-    kwargs.setdefault("check", True)
-    try:
-        return subprocess.run(cmd, **kwargs)
-    except Exception as e:
-        sys.exit(e)
-
-
-def main():
-    CONTAINER_NAME = os.environ["CONTAINER_NAME"]
-
-    build_cmd = [
-        "docker", "buildx", "build",
-        f"--tag={CONTAINER_NAME}",
-        *shlex.split(os.getenv("DOCKER_BUILD_CACHE_ARG", "")),
-        "--file=./ci/lint_imagefile",
-        "."
-    ]
-
-    if run(build_cmd, check=False).returncode != 0:
-        print("Retry building image tag after failure")
-        time.sleep(3)
-        run(build_cmd)
-
-    extra_env = []
-    if os.environ["GITHUB_EVENT_NAME"] == "pull_request":
-        extra_env = ["--env", "LINT_CI_IS_PR=1"]
-    if os.environ["GITHUB_EVENT_NAME"] != "pull_request" and os.environ["GITHUB_REPOSITORY"] == "bitcoin/bitcoin":
-        extra_env = ["--env", "LINT_CI_SANITY_CHECK_COMMIT_SIG=1"]
-
-    run([
-        "docker",
-        "run",
-        "--rm",
-        *extra_env,
-        f"--volume={os.getcwd()}:/bitcoin",
-        CONTAINER_NAME,
-    ])
-
-
-if __name__ == "__main__":
-    main()

.github/workflows/ci.yml

@@ -681,4 +681,6 @@ jobs:
           cache-provider: ${{ needs.runners.outputs.provider }}
 
       - name: CI script
-        run: python .github/ci-lint-exec.py
+        run: |
+          git worktree add ../lint-worktree HEAD
+          ../lint-worktree/ci/lint.py