Fix CI failures and formatting issues

- Mark test corpus/archives as binary in .gitattributes to prevent
  line ending conversion on CI (fixes extract test size mismatch)
- Fix alignment-unsafe struct cast in uc2_dict.c serialize/deserialize
  (use memcpy-based byte access instead; fixes SEGFAULT on CI)
- Fix formatting issues in docs

.gitattributes

@@ -4,3 +4,7 @@ original/UC2_source/**/*.exe binary
 original/UC2_source/**/*.DAT binary
 original/UC2_source/**/*.LIB binary
 original/UC2_source/**/*.PRJ binary
+
+# Test corpus and archives must be byte-exact
+tests/corpus/** binary
+tests/archives/** binary