fix: reformat codebase and fix const-correctness for CI lint

- Reformat all C/H files to match .clang-format (LLVM style)
- Fix 26 cppcheck const-correctness warnings (constParameterPointer,
  constVariablePointer, constVariable)
- Update function declarations in headers to match const parameters

src/shared/metadata.h

@@ -5,12 +5,13 @@
 #include <stdbool.h>
 #include <sys/stat.h>
 
-#define FILE_METADATA_WIRE_SIZE (sizeof(mode_t) + sizeof(uid_t) + sizeof(gid_t) + sizeof(time_t) + sizeof(long))
+#define FILE_METADATA_WIRE_SIZE                                                                    \
+  (sizeof(mode_t) + sizeof(uid_t) + sizeof(gid_t) + sizeof(time_t) + sizeof(long))
 
-void metadata_to_buf(char **buf, FileMetadata *m);
-FileMetadata *metadata_from_buf(char **buf);
-bool metadata_send(int file_descriptor, FileMetadata *m);
-FileMetadata *metadata_receive(int file_descriptor, int *ok);
-void file_restore_metadata(const char *path, FileMetadata *metadata);
+void metadata_to_buf(char** buf, const FileMetadata* m);
+FileMetadata* metadata_from_buf(char** buf);
+bool metadata_send(int file_descriptor, FileMetadata* m);
+FileMetadata* metadata_receive(int file_descriptor, int* ok);
+void file_restore_metadata(const char* path, FileMetadata* metadata);
 
 #endif