Merge origin/main (v1.65.0.0 fork port wave 2) into test-evals-ci-speedup

Second overlapping-wave merge; resolutions compose intent:

- TEST_ROOTS: ours is the superset (main also wired ios-qa/daemon/test;
  ours additionally has ios-qa/scripts + browser-skills). package.json
  'test' keeps routing through the canonical strict runner.
- gbrainAvailable: main fixed the same load-flake with a strictly better
  mechanism (memoized stat-based PATH scan, no subprocess at all) —
  theirs supersedes this branch's memoized-exec probe. Main also made
  the query timeout env-overridable (GSTACK_BRAIN_TIMEOUT_MS).
- Model defaults: adopted main's lib/eval-model.ts abstraction (one
  resolution point, env-overridable per kind) and applied decision D1a
  inside it: capture defaults to Sonnet (Opus opt-in via explicit arg or
  GSTACK_EVAL_MODEL_CAPTURE); test pins updated to follow.
- Parent watchdog: main's rewrite (named parameterized tick, driven
  deterministically by its test via __testInternals__, plus handoff
  suppression semantics from session persistence) supersedes this
  branch's env-tunable interval; adopted their server + test wholesale.
- windows-free-tests: ours (curated bun run test:windows) — main's
  hand-list grew by one more file, which the curated runner subsumes
  automatically; that drift is the reason for D11.
- context-skills 0-for-26 fix: both waves made the IDENTICAL fix; kept
  this branch's comment (carries the receipts).
- .gitignore: main's superset (also ignores Package.resolved — their
  never-commit call; untracked the copy this branch had committed).

Verified: 239-test merge battery green, watchdog 8/8, eval-model 5/5,
actionlint clean, eval:select works.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

lib/eval-model.ts

@@ -0,0 +1,47 @@
+/**
+ * Host-neutral eval/harness model resolution (fork port wave 2, G cluster).
+ *
+ * Model IDs were hardcoded at six call sites across the eval helpers and the
+ * distill bin, so an environment that pins a different model (CI cost
+ * control, a model migration, an air-gapped proxy alias) had to patch source.
+ * One resolution point, env-overridable:
+ *
+ *   GSTACK_EVAL_MODEL_<KIND>  (e.g. GSTACK_EVAL_MODEL_WARMUP) — per-kind
+ *   GSTACK_EVAL_MODEL                                        — global
+ *   explicit argument                                        — caller wins
+ *   per-kind default                                         — last resort
+ *
+ * Kinds and their defaults:
+ *   capture — AskUserQuestion SDK capture runs (quality matters): opus
+ *   warmup  — PTY warm-up ping (cheapest thing that answers): haiku
+ *   distill — free-text distillation (cheap, structured): haiku (pinned)
+ */
+
+// `as const satisfies` keeps EvalModelKind the literal union
+// 'capture' | 'warmup' | 'distill' — a `Record<string, string>` annotation
+// would widen it to string and let any typo through the type gate.
+const DEFAULTS = {
+  // D1a (2026-08 test-infra review): capture runs default to Sonnet, matching
+  // session-runner — the old Opus default was an inconsistency between
+  // runners, not a choice; tests needing Opus pass it explicitly or set
+  // GSTACK_EVAL_MODEL_CAPTURE.
+  capture: "claude-sonnet-4-6",
+  warmup: "claude-haiku-4-5",
+  distill: "claude-haiku-4-5-20251001",
+} as const satisfies Record<string, string>;
+
+export type EvalModelKind = keyof typeof DEFAULTS;
+
+export function resolveEvalModel(
+  kind: EvalModelKind,
+  explicit?: string | null,
+  env: NodeJS.ProcessEnv = process.env,
+): string {
+  if (explicit) return explicit;
+  const perKind = env[`GSTACK_EVAL_MODEL_${kind.toUpperCase()}`];
+  if (perKind) return perKind;
+  if (env.GSTACK_EVAL_MODEL) return env.GSTACK_EVAL_MODEL;
+  const fallback = DEFAULTS[kind];
+  if (!fallback) throw new Error(`resolveEvalModel: unknown kind "${kind}"`);
+  return fallback;
+}