fix: prevent V8 turboshaft WASM Zone OOM during indexing (#298, #293) (#322)

Large multi-language indexes crashed with `Fatal process out of memory:
Zone` on Node 22/24 (including the bundled runtime) — V8's turboshaft
optimizing WASM compiler exhausts its per-compilation Zone arena while
compiling tree-sitter grammars on a background thread, even with tens of
GB free (the Zone is a V8-internal arena, not the JS heap).

Run node with V8 `--liftoff-only`, which keeps grammar compilation on the
Liftoff baseline and never reaches the optimizing tier. Delivered via the
bundled launcher + a one-shot CLI re-exec guard for all other launch
paths. Empirically only `--liftoff-only` stops it (`--no-wasm-tier-up` /
`--no-wasm-dynamic-tiering` do not), and it must be on node's command
line (setFlagsFromString / worker execArgv / NODE_OPTIONS all fail).

Reproduced the exact crash with the real indexer on Node 24.16 against a
2,880-file / 18-language repo and confirmed the fix eliminates it; full
suite + 7 new tests pass. Bumps to 0.9.4.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>