Every Progmasoft-authored file moves from MPL-2.0 WITH
AdditionRef-Progmasoft-Exception-2.0 to LGPL-3.0-or-later, from 0.5.0
on. Catch2-originated files keep BSL-1.0, and the vendored yyjson and
pugixml keep MIT.

- LICENSES/ holds the LGPL-3.0 text and the GPL-3.0 text it builds on,
  both as published by the FSF; the MPL-2.0 and Progmasoft Exception
  texts go, since no file uses them any more.
- Five files that came from Catch2 and were rewritten by Progmasoft
  (.clang-format, the issue and pull request templates, SECURITY.md)
  keep Catch2's notice next to Progmasoft's and say
  LGPL-3.0-or-later AND BSL-1.0.
- //tools:check expects the new header of Progmasoft files; the
  amalgamation notes say LGPL-3.0-or-later and the amalgamated files
  are regenerated; meson's project license is BSL-1.0 and
  LGPL-3.0-or-later.
- README gains a License section; LICENSES/README.md, contributing.md
  and progmasoft-catch3.md describe the new split and that releases
  before 0.5.0 keep the license they were published under.

Every commit to Progmasoft's files since the fork is the maintainer's.

Claude-Session: https://claude.ai/code/session_01Ji7xZMYjc4zankoc7hGBE1

Version 1.1 left programs built with Progmasoft tools under MPL-2.0 duties
for the code the tools place in them, and left other cases unclear.
Version 2.0 adds a generated code permission, covers runtime and standard
libraries, compiler transformations, interfaces and examples, and settles
how a file is identified and how to tell recipients about source.

Every project SPDX expression moves to AdditionRef-Progmasoft-Exception-2.0.
The older texts stay, because released versions name them.

Catch2 compatibility means the API tests are written in: the macros, such
as TEST_CASE and REQUIRE, and the Catch:: namespace. It does not mean
Catch2's build names or header paths. find_package(Catch2) found Catch3,
and a project using both frameworks met two packages, two sets of targets,
two Catch.cmake modules and two catch2/ header trees with the same names.

Build names:
- CMake: project and package Catch3, targets Catch3::Catch3 and
  Catch3::Catch3WithMain, libraries Catch3 and Catch3Main, options
  CATCH3_*, lib/cmake/Catch3 with Catch3Config, and pkg-config catch3 and
  catch3-with-main. The version is Catch3's, 0.3.0, compatible within a
  minor version.
- The CMake scripts are Catch3.cmake (catch3_discover_tests),
  Catch3AddTests.cmake and Catch3ShardTests.cmake
  (catch3_add_sharded_tests); the helpers they define at ctest time have a
  catch3_ prefix. ParseAndAddCatchTests.cmake, deprecated upstream, is gone.
- Bazel //:catch3 and //:catch3_main, Meson catch3 and catch3-with-main
  (with override_dependency), Xmake catch3 and catch3_main, Premake Catch3
  and Catch3WithMain. Visual Studio projects get GUIDs of their own.
- The Progmasoft::Catch3 target and package are gone: property testing
  and snapshots are part of Catch3::Catch3. Their sources now build with
  the library's warning flags, so property failures are built field by
  field (no missing initializers) and the default property name is a
  thread-local pointer to the name its scope owns (no global destructor).

Headers: the engine moved from src/catch2 to src/Progmasoft/Catch3 with
Progmasoft names, so <catch2/catch_test_macros.hpp> is
<Progmasoft/Catch3/TestMacros.hpp>, <catch2/matchers/catch_matchers_string.hpp>
is <Progmasoft/Catch3/Matchers/String.hpp>, and interface headers are named
after their interface, such as Interfaces/IConfig.hpp. Include guards
became #pragma once. The installed headers go to include/Progmasoft.
src/Progmasoft/Context.cpp is StrategyContext.cpp, so no two sources share
a file name.

tools/scripts/upstreamFiles.txt lists the files that come from Catch2.
The license check expects BSL-1.0 on them and Progmasoft's header on the
rest of src/Progmasoft; the convenience-header check, the amalgamation
script and the surrogate tests take the engine's headers from it. The
amalgamated files are regenerated. The header-guard workflow checks for
#pragma once instead of checkguard.

Documents, the README and the release notes describe the new names.

A test that called exit() crashed its worker with SIGSEGV on Linux and
macOS. The exit hook read Catch2's captured output through a scoped
deactivation, which switched the capture back on; libstdc++ then flushed
std::cout at exit into a capture buffer that static destruction had
already freed. RunContext::endCapture() now ends the capture for good and
returns what it held, so the standard streams are their own again.

A JUnit, JSON or trace report that could not be written was only
reported on stderr, and a run whose tests passed still exited with 0, so a
build server could miss it. Such a run now exits with 1; failed tests
still exit with 42.

Integration tests of the runner's output move their helpers into
RunnerFixtureClient.hpp and cover --version, --help, the listing modes, a
bad option, exit codes 1 to 4, -v, -q, --slowest, colours, --analytics
in text and JSON, and Bazel's test environment.