One blank line between sections and a mailto link for the reporting
address, as Codacy's markdownlint asks; the text is unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ji7xZMYjc4zankoc7hGBE1

The code of conduct inherited from Catch2 was Contributor Covenant 1.4.
It becomes version 3.0, the text every public Progmasoft repository now
carries: reports go to support@progmasoft.com, read by the maintainers
as the Community Moderators, and the enforcement ladder applies as the
Covenant writes it. The file keeps the Covenant's CC-BY-SA-4.0 license.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ji7xZMYjc4zankoc7hGBE1

Catch3 is maintained by Progmasoft, but the repository still carried
Catch2's funding links, its maintainer list and GPG keys, a Code of Conduct
contact at a Catch2 maintainer's address, its lists of users, its release
process and release scripts, its AppVeyor configuration and its logos.

- Removed FUNDING.yml, MAINTAINERS.md, appveyor.yml with the AppVeyor and
  OpenCppCoverage helpers, Catch2's user lists, why-catch, release process
  and deprecations pages, its two logos and the major/minor/patch release
  scripts. releaseCommon.py keeps only what the amalgamation reads.
- The Code of Conduct sends reports to support@progmasoft.com.
- contributing.md and release-notes.md are written for Catch3; Catch2's
  release history is linked upstream.
- CMake, pkg-config and Doxygen name Catch3 and its repository; the
  amalgamated files say which Catch3 version and which Catch2 engine they
  come from.