fix(ci): repair the PR-title check, which could never pass

The `regexp` input in PRECOMMITS.yml was written with doubled backslashes
inside a single-quoted YAML scalar, which has no backslash escapes. Every
`\\` therefore reached JavaScript as a literal backslash, so the class
`[a-z,A-Z,0-9,\\-,\\_,\\/,:]` contained a `\` (0x5C) to `,` (0x2C) range
and `new RegExp` threw before reading any title:

    SyntaxError: Invalid regular expression: Range out of order in
    character class

The job died in five seconds whatever the pull request was called, and the
`pre-commit run` step after it never executed - so the workflow verified
nothing at all.

Replace it with the pattern the repository already uses for commit
messages (the `validate-commit-msg` hook), so one convention governs both
and a title accepted locally is accepted in CI. Scope stays optional and
the type list matches the hook, which is what the history on `main`
actually uses.

tests/test_ci_workflow_config.py compiles the pattern, asserts it stays
identical to the hook entry, and checks it against real titles from
`main` plus malformed ones.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S1CErYvpggWAogJ9MDVqj4

Author: claude

.github/workflows/PRECOMMITS.yml

@@ -29,7 +29,14 @@ jobs:
       - name: Check Pull Request Title
         uses: Slashgear/action-check-pr-title@main
         with:
-          regexp: '(break|build|ci|docs|feat|fix|perf|refactor|style|test|ops|hotfix)\\([a-z,A-Z,0-9,\\-,\\_,\\/,:]+\\)(:)\\s{1}([\\w\\s]+)' # Regex the title should match.
+          # Kept identical to the `validate-commit-msg` hook in
+          # .pre-commit-config.yaml so a title that passes locally passes here.
+          # The previous pattern was double-escaped for a YAML single-quoted
+          # scalar (which has no backslash escapes), so `[a-z,A-Z,0-9,\-,...]`
+          # reached JavaScript containing a `\`-to-`,` range and RegExp threw
+          # "Range out of order in character class" before reading any title -
+          # the check could never pass, whatever the PR was called.
+          regexp: '^(break|build|ci|docs|feat|fix|perf|refactor|style|test|ops|hotfix|release|maint|init|enh|revert|reformat)(\([\w.,\-()/]+\))?(!)?:\s.+$'
       - name: Getting changed files list
         id: files
         uses: jitterbit/get-changed-files@v1

tests/test_ci_workflow_config.py

@@ -0,0 +1,85 @@
+r"""The PR-title check in CI must use a pattern that actually compiles.
+
+``.github/workflows/PRECOMMITS.yml`` passed its ``regexp`` through a
+single-quoted YAML scalar, which has no backslash escapes, so every ``\\`` in
+the pattern reached JavaScript as a literal backslash. The character class
+``[a-z,A-Z,0-9,\\-,\\_,\\/,:]`` therefore contained a range from ``\`` (0x5C)
+to ``,`` (0x2C) and ``new RegExp`` threw::
+
+    SyntaxError: Invalid regular expression: Range out of order in character class
+
+The action crashed before reading any title, so the job failed in five seconds
+whatever the pull request was called - and the ``pre-commit run`` step after it
+never executed. Nothing in CI could pass this workflow.
+"""
+
+from __future__ import annotations
+
+import re
+from pathlib import Path
+
+import pytest
+import yaml
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+WORKFLOW = REPO_ROOT / ".github" / "workflows" / "PRECOMMITS.yml"
+PRE_COMMIT_CONFIG = REPO_ROOT / ".pre-commit-config.yaml"
+
+pytestmark = pytest.mark.skipif(not WORKFLOW.exists(), reason="workflow not present")
+
+
+def _pr_title_pattern() -> str:
+    workflow = yaml.safe_load(WORKFLOW.read_text(encoding="utf-8"))
+    steps = workflow["jobs"]["pre-commit-checks"]["steps"]
+    step = next(s for s in steps if s.get("name") == "Check Pull Request Title")
+    return step["with"]["regexp"]
+
+
+def _commit_msg_pattern() -> str:
+    config = yaml.safe_load(PRE_COMMIT_CONFIG.read_text(encoding="utf-8"))
+    hook = next(h for repo in config["repos"] for h in repo["hooks"] if h["id"] == "validate-commit-msg")
+    return hook["entry"]
+
+
+def test_the_pr_title_pattern_compiles():
+    """A pattern that does not compile fails every pull request."""
+    re.compile(_pr_title_pattern())
+
+
+def test_the_pr_title_pattern_matches_the_commit_message_hook():
+    """One convention, one pattern.
+
+    A title that the local ``commit-msg`` hook accepts must not be rejected by
+    CI, and vice versa; the two drift apart the moment they are written twice.
+    """
+    assert _pr_title_pattern() == _commit_msg_pattern()
+
+
+@pytest.mark.parametrize(
+    "title",
+    [
+        "refactor: production readiness audit",
+        "fix(core): restore integrations re-exports",
+        "feat(ui/backend): add the security module",
+        "docs: document model serving",
+        "maint: sync version to 2.2.0 across all sources [skip ci]",
+        "fix!: drop the deprecated endpoint",
+    ],
+)
+def test_titles_the_project_already_uses_are_accepted(title):
+    """Every one of these appears in the history of ``main``."""
+    assert re.match(_pr_title_pattern(), title), f"{title!r} is rejected by the PR-title check"
+
+
+@pytest.mark.parametrize(
+    "title",
+    [
+        "chore: not one of the allowed types",
+        "a title with no type at all",
+        "feat:no space after the colon",
+        "feat: ",
+    ],
+)
+def test_malformed_titles_are_still_rejected(title):
+    """The check has to keep checking something."""
+    assert not re.match(_pr_title_pattern(), title), f"{title!r} should not pass the PR-title check"