PortableResourceMacro

Split content into pieces small enough to be emitted as individual JVM constant-pool string literals. A CONSTANT_Utf8 entry stores its length in an unsigned 16-bit field, so it cannot exceed 65535 bytes of modified UTF-8. A single char encodes to at most 3 modified-UTF-8 bytes (lone surrogates included), so chunking at maxChunkChars characters keeps every chunk under the limit regardless of content. Splitting mid-surrogate-pair is safe: re-concatenating the chunks at runtime reproduces the original string exactly.