fix: replace heredoc with printf in qt.conf generation to fix YAML syntax error

Heredoc closing delimiter at column 0 inside a YAML run: block causes
a parse error. Replaced with a single printf call that produces
identical output without any indentation constraints.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: tilakpatel22

.github/workflows/build-cpp.yml

@@ -454,12 +454,7 @@ jobs:
           # Without this, Qt falls back to hardcoded build-time paths which
           # don't exist on a clean machine and can cause plugin load failures.
           # ----------------------------------------------------------------
-          cat > dist/qt.conf <<'QTCONF'
-[Paths]
-Prefix = .
-Plugins = .
-Libraries = .
-QTCONF
+          printf '[Paths]\nPrefix = .\nPlugins = .\nLibraries = .\n' > dist/qt.conf
 
           # ----------------------------------------------------------------
           # Copy app resources and Python analytics scripts