Move dispatcher-facing host effects out of volume_server_block.go into
blockcmd while keeping server-owned cache/state semantics in weed/server.
Document Batch 10 delivery and Batch 11 stop-line review so the
separation line closes without over-extracting readiness-state mutation.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>