Implement `bytesIndexOf` foreign function supporting optional start offset for searching byte sequences. Add `serverAcceptBatch` and `serverPendingCount` to net module for batch accepting connections and querying pending queue size. Refactor `stdinFileTimerCallback` to pass read bytes to Wren callback instead of null, with separate handling for EOF. Introduce `coverage_64bit` build config with gcov flags, plus `coverage`, `valgrind`, `clean-coverage`, and `publish` phony targets in Makefile. Fix memory leak in regex by nullifying freed pointers on allocation failure.
Add `// skip:` annotation to read_byte_eof.wren, read_line.wren, and read_line_eof.wren
to prevent test failures on non-linux platforms until the underlying issue is fixed.
Add lexer support for `TOKEN_INTERPOLATION` to split string literals at interpolation points, introduce `MAX_INTERPOLATION_NESTING` limit of 8, and compile interpolated strings by emitting calls to `String.interpolate_()`. Optimize list and map literal construction with new `addCore_` primitives to reduce stack churn. Update `String`, `List`, and `Map` `toString` methods in core library to use interpolation syntax, and migrate all benchmark and test files from explicit concatenation to interpolated strings.
