Publishing after spawn let a loop that dies immediately reset the state
first, so the later publish pinned it at Muxed with a dead handle
forever. Also adds a test pinning open-before-data ordering across many
concurrently opened channels, and drops an unused Clone derive.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZ49AbZJYfm8NTp5yDPMab
Replace cumulative accounting (granted/received) with remaining credit
tracking to prevent u32 overflow after 4 GiB of data on a single channel.
Wire behavior is identical, but the fix allows large file transfers
without mid-stream channel closure.
Add regression test for 8 GiB transfer to verify fix.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZ49AbZJYfm8NTp5yDPMab
