feat(compat): version compatibility profiles for the Lua sandbox

[fatal10110]

What

Make the engine emulate the Lua sandbox behavior of a chosen Redis/Valkey version via a profile option.

Researched the sandbox setup (script_lua.c; 6.2 = scripting.c) across redis 6.2/7.0/7.2/7.4/8.0 and valkey 7.2/8.0/8.1. Only three behaviors actually differ — everything else (cjson/cmsgpack/struct/bit/math/table/string, deny of dofile/loadfile, globals protection, setresp/RESP3) is constant since 6.2:

behavior	available in
print global	redis 6.2 only (enters deny_list at 7.0)
os library	redis 7.4+, valkey 8.0+
server.* alias	valkey 8.0+ only — redis 8.0 has no server alias

How

Three orthogonal flags (COMPAT_PRINT/OS/SERVER_ALIAS) as a u8 bitmask, passed via a new set_compat() WASM export and consumed by a shared setup_state() (dedupes the near-identical init/reset). No per-version build fork — one binary, per-engine choice.

await load({ profile: "redis6.2" });                  // print kept, no os/server
await load({ profile: "redis7.2", compat: { os: true } }); // override one flag
await load();                                          // default ≈ valkey8.0 (unchanged)

profile is a named preset over the version matrix; compat overrides individual flags. Default (no profile) preserves prior behavior, so this is non-breaking.

Test

• 6 new compat ... tests in test/engine.test.ts covering each profile + override + default.
• WASM rebuilt (Docker); full suite 187 pass / 0 fail.

🤖 Generated with Claude Code