[P2][dst] Expand DST workload fuzz for binary keys and sortedness asserts #29

Summary

DST workload uses 16 short ASCII keys and "vN" values. No fuzz of binary keys, empty values, large payloads, or lens-style composite keys with 0x00 separators. Recovered sortedness is never asserted post-recovery.

Audit ID: Section 3 Medium — Wave 2

Root cause

src/sim/workload.ts ~L88 — narrow alphabet.

Fix

Add seeded round-trip fuzz profile:

1. Generate random Uint8Array keys/values, lengths 0..N (cap N for CI speed).
2. Random ops: set/delete/getRange in transactions.
3. Crash/recover cycles.
4. Assert: deep-equal store + entries sorted by compareKeys after recovery.
5. After B5 lands: aliasing/mutation tests on recovered buffers.

Acceptance criteria

• New DST seed(s) in matrix.
• Sorted invariant checked after every recovery.
• Binary + empty + large payloads covered.
• bun run gate green.

Related issues

• B5 — buffer copy contract
• Explore kernel durability hardening (WAL record headers, fsync-batching mode, expanded DST fault profiles) #9 — DST expansion

Verification

bun run gate