fix(tui): pass --expose-gc as node argv instead of NODE_OPTIONS

[YarrowQiao]

Summary

hermes --tui fails to start on every modern Node release with:

node: --expose-gc is not allowed in NODE_OPTIONS

_launch_tui() was appending --expose-gc to NODE_OPTIONS before spawning the TUI. Node restricts NODE_OPTIONS to a small allowlist (so anything able to set env vars on a node child can't unilaterally enable arbitrary capabilities) — --expose-gc is not on that list and never has been. It must be passed as a direct argv flag.

The intent (manual GC for long sessions to avoid fatal-OOM on large transcripts / reasoning blobs) is preserved by inserting --expose-gc directly into the node argv inside _make_tui_argv() — same effect, but actually allowed.

--max-old-space-size=8192 stays in NODE_OPTIONS because it is allowlisted, and keeping it there means downstream node spawns inherit the same heap cap without re-threading the flag through every spawn site.

The dev paths (tsx src/entry.tsx and npm start fallback) are intentionally left alone — they don't accept node flags directly, and the production dist path is the one users actually hit via hermes --tui. The shebang in ui-tui/src/entry.tsx already documents the intended flags for direct execution.

Repro (before fix)

$ hermes --tui
/usr/bin/node: --expose-gc is not allowed in NODE_OPTIONS

Test plan

• hermes --tui starts without the --expose-gc is not allowed error on Node v18.20.8 (Linux/WSL2)
• import hermes_cli.main succeeds (no syntax regressions)
• Manual smoke: long-running TUI session still has 8GB heap and a callable global.gc()

[alt-glitch]

Duplicate of #17200 which addresses the same --expose-gc NODE_OPTIONS issue (fix for #17187).

[teknium1]

Merged via PR #29998 — your commit was cherry-picked onto current main with your authorship preserved in git log (2ea7cf2). Added a small sibling-site fix on top (wheel-bundled launch path was missing --expose-gc too). Thanks for the clean fix and the great commit message explaining the NODE_OPTIONS allowlist rationale! Closes #17187 too.