ci: add static analysis, sanitizers, and formatting enforcement

Add Tier 1 review automation to catch issues before human review:

- Add cppcheck and clang-format to CI lint job
- Add sanitizer matrix (ASan + TSan) CI job
- Enable -Wextra -Wpedantic -Werror in CI build
- Add SANITIZER and STRICT_WARNINGS CMake options
- Add .clang-format for consistent code style
- Update Dockerfile with cppcheck and clang-format
- Fix sign-compare and unused-parameter warnings for -Werror

src/shared/protocol.c

@@ -68,7 +68,7 @@ bool send_n_data(int file_descriptor, void *data, size_t data_size) {
   log_message(LOG_LEVEL_DEBUG, "    Sending n Data: %zu", data_size);
   int fd = io_fd(io_write_fd, file_descriptor);
   ssize_t total_bytes_send = 0;
-  while (total_bytes_send < data_size) {
+  while ((size_t)total_bytes_send < data_size) {
     size_t chunk = data_size - total_bytes_send;
     if (io_bwlimit > 0 && chunk > 65536)
       chunk = 65536;