Fix YAML syntax error in release.yml heredoc

[RAprogramm]

Problem

Release workflow fails with startup_failure due to YAML syntax error in heredoc delimiters.

Root Cause

Lines 125-159 and 161-169 in .github/workflows/release.yml use heredoc with quoted delimiters:

cat > "${TMPDIR}/src/main.rs" << 'RUST_EOF'
cat > "${TMPDIR}/Cargo.toml" << 'TOML_EOF'

GitHub Actions YAML parser fails on these quoted heredoc delimiters.

Solution

Remove quotes from heredoc delimiters or use alternative syntax.

Evidence

• Run 18441530077 failed with startup_failure
• Workflow file issue detected by GitHub Actions