Give Catch3 its own build names and headers

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.

1 files changed, 125 insertions, 0 deletions

diff --git a/src/Progmasoft/StrategyContext.cpp b/src/Progmasoft/StrategyContext.cpp
new file mode 100644
index 00000000..476b41de
--- /dev/null
+++ b/src/Progmasoft/StrategyContext.cpp
@@ -0,0 +1,125 @@
+// Copyright (c) 2026 Progmasoft.
+// SPDX-License-Identifier: MPL-2.0 WITH AdditionRef-Progmasoft-Exception-1.1
+#include <Progmasoft/Catch3/Strategy/Context.hpp>
+#include <string>
+#include <utility>
+
+namespace Progmasoft::Catch3
+{
+
+    namespace
+    {
+
+        thread_local TrialRecord *currentRecord = nullptr;
+        thread_local const std::string *defaultPropertyName = nullptr;
+
+    } // namespace
+
+    namespace Detail
+    {
+
+        TrialRecord *
+        CurrentTrialRecord() noexcept
+        {
+            return currentRecord;
+        }
+
+        TrialRecordScope::TrialRecordScope(TrialRecord &record) noexcept
+            : previous_(currentRecord)
+        {
+            currentRecord = &record;
+        }
+
+        TrialRecordScope::~TrialRecordScope()
+        {
+            currentRecord = previous_;
+        }
+
+        void
+        RecordPropertyFailure(std::string_view expression,
+                              std::string_view file,
+                              std::size_t line)
+        {
+            if (currentRecord == nullptr)
+            {
+                return;
+            }
+            // Only the first failure of a trial counts: it is the one the
+            // body stopped at.
+            if (!currentRecord->Failure.has_value())
+            {
+                currentRecord->Failure = "CATCH3_PROPERTY_ASSERT( "
+                                         + std::string(expression) + " ) at "
+                                         + std::string(file) + ":"
+                                         + std::to_string(line);
+            }
+        }
+
+        void
+        RecordPropertyFailureMessage(std::string message)
+        {
+            if (currentRecord != nullptr && !currentRecord->Failure.has_value())
+            {
+                currentRecord->Failure = std::move(message);
+            }
+        }
+
+        std::string
+        DefaultPropertyName()
+        {
+            return defaultPropertyName != nullptr ? *defaultPropertyName
+                                                  : std::string();
+        }
+
+        PropertyNameScope::PropertyNameScope(std::string name)
+            : name_(std::move(name))
+            , previous_(defaultPropertyName)
+        {
+            defaultPropertyName = &name_;
+        }
+
+        PropertyNameScope::~PropertyNameScope()
+        {
+            defaultPropertyName = previous_;
+        }
+
+    } // namespace Detail
+
+    void
+    Note(std::string text)
+    {
+        if (currentRecord != nullptr)
+        {
+            currentRecord->Notes.push_back(std::move(text));
+        }
+    }
+
+    void
+    Classify(bool condition, std::string label)
+    {
+        if (currentRecord != nullptr && condition)
+        {
+            currentRecord->Labels.push_back(std::move(label));
+        }
+    }
+
+    void
+    Cover(double requiredPercentage, bool condition, std::string label)
+    {
+        if (currentRecord != nullptr)
+        {
+            currentRecord->Covers.push_back(
+                { std::move(label), requiredPercentage, condition });
+        }
+    }
+
+    void
+    Target(double score, std::string label)
+    {
+        if (currentRecord != nullptr)
+        {
+            currentRecord->Targets.push_back({ std::move(label), score });
+        }
+    }
+
+} // namespace Progmasoft::Catch3