test(storage): verify multiblock restart replay

[kaikisegfault]

Summary

• exercise mixed, empty, entirely unadmitted, and duplicate-admitted blocks across four durable heights
• close and fully reopen before every continued commit
• compare every durable commit and head with an independent in-memory kernel and verify exact journal counts
• repeat final reopen to prove stable replay

Verification

• PROTOCOL_STACK_PRESET=gcc-debug tools/verify.sh — 16/16
• ASAN_OPTIONS=detect_leaks=0 PROTOCOL_STACK_PRESET=gcc-sanitizers tools/verify.sh — 16/16
• PROTOCOL_STACK_PRESET=clang-debug tools/verify.sh — 16/16
• ASAN_OPTIONS=detect_leaks=0 PROTOCOL_STACK_PRESET=clang-sanitizers tools/verify.sh — 19/19, including 3 fuzz smoke tests
• Python compileall, shell syntax, JSON/TOML/YAML parsing, internal Markdown links, identity, and diff checks passed

Refs #11