fix(build): statically link libc++ on Linux to remove runtime LLVM dependency

- Add -static-libstdc++ linker flag on Linux/Clang builds so libc++ is
  embedded in the binary rather than required as a runtime .so
- Simplify Dockerfile back to just libssl3 + libpq5; no LLVM apt repo needed

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

Author: guzman109

CMakeLists.txt

@@ -72,6 +72,11 @@ target_link_libraries(${PROJECT_NAME}
         OpenSSL::Crypto
 )
 
+# Statically link libc++ on Linux/Clang so the runtime container needs no LLVM packages.
+if(CMAKE_SYSTEM_NAME STREQUAL "Linux" AND CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+    target_link_options(${PROJECT_NAME} PRIVATE -static-libstdc++ -lc++abi)
+endif()
+
 target_compile_definitions(${PROJECT_NAME}
     PRIVATE
         GLZ_ENABLE_SSL

Dockerfile

@@ -5,14 +5,10 @@
 # =============================================================================
 FROM debian:bookworm-slim
 
-RUN apt-get update && apt-get install -y wget ca-certificates \
-    && wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc \
-    && echo "deb http://apt.llvm.org/bookworm/ llvm-toolchain-bookworm-21 main" >> /etc/apt/sources.list.d/llvm-21.list \
-    && apt-get update && apt-get install -y \
+RUN apt-get update && apt-get install -y \
     libssl3 \
     libpq5 \
-    libc++1-21 \
-    libc++abi1-21 \
+    ca-certificates \
     && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app