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

A review of the import found ways for a failure to disappear or for the
import to reach too far.

- CTRF's retryAttempts ends before the final attempt, which was dropped when
  its outcome matched the one before it.
- TAP names tests only within a stream, so a failure in one file and a pass
  under the same name in another merged into a flaky pass. The path given to
  --import is now the class of a stream's tests.
- A failure followed by a skip with the same identifier read as skipped.
- Directives are whole words: TODOING is not TODO. SKIPPED and SKIPPING stay
  directives, as harnesses treat them.
- Verdicts that alternate count as flaky only under an explicit
  --import-revision. HEAD says nothing about a dirty checkout or a report from
  another one, and two such events could quarantine a real failure.
- --import-name no longer redirects the history of a normal test run.
- Importing does not depend on the tests registered in the binary.

Tests Catch3 does not run had no history, flaky detection or quarantine.
--import=FILE reads a report instead of running tests and sends it through
the analysis, history and reports of a run: JUnit with Surefire's reruns,
xUnit.net v2, TRX, TAP 12 to 14, CTRF, Catch3's own --json report and
catch3-results, a small JSON Lines format for tools with none of these.

Results that share an identifier are attempts at one test, so a report of a
rerun gives a flaky test. --import-revision says what was tested: a verdict
that changes on one revision also counts as flaky. --import-name keeps the
results in a history of their own, which --analytics reads too. A TAP stream
that ends early fails instead of reading as a run that passed.

The amalgamation script now accepts a relative include of the third-party
wrappers, because pugixml is included from a second directory.