Inserts improved prompt for migration

scripts/run-entire-copilot-migration.sh

@@ -47,34 +47,7 @@ echo
 echo "== Checkpoints vor der Session =="
 entire checkpoint list
 
-cat <<PROMPT
-
-Use this prompt in Copilot CLI:
-
-Migrate the legacy Qt5/C++11 desktop application to Qt6/C++23.
-
-Requirements:
-- Read the legacy source project from ${PROJECT_DIR}
-- Write the migrated project into qt6-after/qt6-migrated-benchmark
-- Do not modify the legacy source tree in place
-- Update CMake from Qt5 to Qt6
-- Keep Core, Gui, and Widgets explicitly linked
-- Replace QRegExp with QRegularExpression
-- Replace QDesktopWidget / QApplication::desktop() usage with QScreen-based Qt6 APIs
-- Remove legacy QTextCodec usage and use modern Qt6-safe text handling
-- Modernize old SIGNAL/SLOT syntax to function-pointer connect syntax
-- Replace legacy null pointer literals with nullptr
-- Preserve the .ui and .qrc integration
-- Preserve application behavior
-- Upgrade the project from C++11 to C++23
-- For every code change inside a method, add at least three tests covering the changed behavior
-- Place all generated tests in qt6-after/qt6-migrated-benchmark/tests
-- Update CMake so the migrated application and all tests build successfully with CTest
-- Keep the test file naming compatible with repository policy checks
-- Briefly explain each migration change
-PROMPT
-
-copilot --model "${COPILOT_MODEL}"
+envsubst < migration.prompt | copilot --model "${COPILOT_MODEL}"
 
 echo
 echo "== Git status after Copilot session =="