Low-mem enabler — default unchanged (8192 for both engines), low blast radius.
- Heap knob honored by BOTH engines via the shared NODE_OPTIONS injection:
HERMES_TUI_HEAP_MB env (highest precedence, matches the HERMES_TUI_ENGINE
env-first pattern) > display.tui_heap_mb config (minimal early YAML read,
mirrors _config_tui_engine_early) > the existing cgroup-aware default. The
override REPLACES the 8192 default inside _resolve_tui_heap_mb (D3): low =
the low-mem opt-in, high = raise the ceiling. The cgroup-fit 75% clamp still
applies on top, so an override never exceeds the container. A non-secret
behavioral setting → config.yaml, NOT the denylisted NODE_OPTIONS bridge.
- --expose-gc added to the OpenTUI argv in _make_opentui_argv (D4, parity with
Ink which already has it). Must be an argv flag — Node rejects --expose-gc in
NODE_OPTIONS. Makes global.gc() a real call so the engine's GC hooks
(/heapdump; W2's proactive idle GC) work instead of silent no-ops. Verified:
`node --expose-gc -e 'typeof global.gc'` → "function" (vs "undefined").
Tests: TestHeapOverride (env>config precedence, cgroup clamp on a too-high
override, low override honored under a big container, garbage/non-positive
fall-through) + TestExposeGcOnOpenTuiArgv. test_tui_heap_sizing.py 29 passed.
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