Move the tools from Python to C++17 and Bazel

The scripts in use become programs run with `bazelisk run //tools:<tool>`,
and arguments follow `--`:

  amalgamate     the single-file distribution; --check only compares it
  check          licenses, convenience headers, header guards, file names,
                 versions and whether the distribution is up to date
  third-party    compares third_party/ with its archives, or writes it
  version        prints the version, or moves every place that states it
  release-notes  prints a section of the release notes
  repo-info      reports the checkout and the tools on PATH; --json writes
                 it through yyjson, with the fields of Tala's repo-info

amalgamate writes what the Python script wrote, byte for byte, except for
the time of generation. That line is gone so that the output is
deterministic and --check can compare it.

MODULE.bazel now pins the archives of third_party/ by version and sha256,
so Bazel fetches and checks them instead of a tool of ours, and Renovate
reads the versions there.

Scripts nobody used are gone: fixWhitespace, updateDocumentSnippets,
buildAndTest, and updateDocumentToC, which rewrote unrelated documents.
CheckConvenienceHeaders leaves CTest, since //tools:check runs it in CI.
The Python of tests/TestScripts stays: those are tests, not tools.

1 files changed, 49 insertions, 0 deletions

diff --git a/tools/ReleaseNotesMain.cpp b/tools/ReleaseNotesMain.cpp
new file mode 100644
index 00000000..1eb67469
--- /dev/null
+++ b/tools/ReleaseNotesMain.cpp
@@ -0,0 +1,49 @@
+// Copyright (c) 2026 Progmasoft.
+// SPDX-License-Identifier: MPL-2.0 WITH AdditionRef-Progmasoft-Exception-2.0
+
+// bazelisk run //tools:release-notes -- [version]
+//
+// Prints a section of docs/release-notes.md, of the current version without
+// an argument, for the text of a GitHub release.
+
+#include <iostream>
+#include <string>
+
+#include "tools/Repository.hpp"
+#include "tools/Versions.hpp"
+
+int
+main(int argc, char **argv)
+{
+    using namespace Progmasoft::Catch3::Tools;
+
+    if (argc > 2)
+    {
+        std::cerr << "usage: bazelisk run //tools:release-notes -- [version]\n";
+        return 2;
+    }
+    const auto root = RepositoryRoot();
+    if (!root)
+    {
+        std::cerr << "run this tool with bazelisk run\n";
+        return 2;
+    }
+    Problems problems;
+    const auto version = argc == 2 ? std::optional<std::string>{ argv[1] }
+                                   : CurrentVersion(*root, problems);
+    const auto notes
+        = ReadOrReport(*root / "docs" / "release-notes.md", problems);
+    if (!version || !problems.empty())
+    {
+        return Finish(problems);
+    }
+    const auto section = ReleaseNotesOf(notes, *version);
+    if (!section)
+    {
+        problems.push_back("no section for " + *version
+                           + " in docs/release-notes.md");
+        return Finish(problems);
+    }
+    std::cout << *section;
+    return 0;
+}