Merge origin/main (v1.64.1.0) into garrytan/time-attack-fork-review

The code-smell wave refactored the tunnel start into the staged
startTunnel helper; the merge adopts that structure and threads this
branch's truthful consent strings through its consent parameter (the
receipt now names the isPairAgentEnabled gate at both call sites). The
eng-review PTY warmup takes both improvements: main's resolveClaudeBinary
fallback and this branch's resolveEvalModel kind. Resolver imports
union; carve budgets take the larger of both waves' measured values
(parity suite green on the merged tree); conflicted generated SKILL.md
files regenerated from resolved sources. VERSION stays 1.65.0.0 over
main's 1.64.1.0; CHANGELOG stacks 1.65.0.0 > 1.64.1.0 > 1.64.0.0.

scripts/resolvers/preamble.ts

@@ -72,13 +72,17 @@ export { generateTestFailureTriage } from './preamble/generate-test-failure-tria
 // T3: T2 + repo-mode + search
 // T4: (same as T3 — TEST_FAILURE_TRIAGE is a separate {{}} placeholder, not preamble)
 //
-// Skills by tier:
-//   T1: browse, setup-cookies, benchmark
-//   T2: investigate, cso, retro, doc-release, setup-deploy, canary, context-save, context-restore, health
-//   T3: autoplan, codex, design-consult, office-hours, ceo/design/eng-review
-//   T4: ship, review, qa, qa-only, design-review, land-deploy
+// Which skill gets which tier lives in each template's frontmatter
+// (`preamble-tier: N`). Every template that resolves {{PREAMBLE}} must
+// declare it — there is no default.
 export function generatePreamble(ctx: TemplateContext): string {
-  const tier = ctx.preambleTier ?? 4;
+  const tier = ctx.preambleTier;
+  if (tier === undefined) {
+    throw new Error(
+      `Missing preamble-tier frontmatter in ${ctx.tmplPath}: every template that ` +
+      `resolves {{PREAMBLE}} must declare 'preamble-tier: N' (1-4).`
+    );
+  }
   if (tier < 1 || tier > 4) {
     throw new Error(`Invalid preamble-tier: ${tier} in ${ctx.tmplPath}. Must be 1-4.`);
   }