Fix: Brought back suppressions.txt

cppcheck/suppressions.txt

@@ -0,0 +1,19 @@
+# Suppress Cppcheck noise for this GCC 16 / C++26 course project.
+#
+# Prefer: cmake --build cmake-build-debug-gcc-16-cpp26 --target cppcheck_modules
+# Disable the CLion Cppcheck plugin — it analyzes headers in isolation.
+
+# GCC / libstdc++ / contracts false positives (especially in CLion plugin mode)
+missingIncludeSystem
+syntaxError
+
+# Third-party (Google Test / Google Mock) — analyzed by cppcheck_project
+*:_deps/*
+
+# Course exercise stubs — intentional teaching patterns (TODO implementations)
+passedByValue:*modules/*
+useStlAlgorithm:*modules/*
+functionStatic:*modules/*
+uninitMemberVarNoCtor:*modules/*
+constVariable:*modules/*
+bitwiseOnBoolean:*modules/*