TestFetchTooLargeIsStreaming asserted the server wrote at most 64 KiB, but
the handler keeps flushing 64-byte chunks until the client's close propagates,
which under a loaded full-suite run exceeds that (observed ~80 KiB). The
assertion guards against unbounded buffering toward 8 MiB, so 1 MiB keeps
the intent and removes the flake.
- Cover private and public IPv4 embeddings across NAT64 and 6to4
- Exercise unsafe transition literals through the production dial control
- Require classifier-owned IPv4-mapped normalization
