chore: sync the frontend template from 4dc033c to 8157ad4

The product was materialized from the template at `4dc033c` and has stayed
on it through 43 template commits, so it was missing all three rounds of
adapter remediation — including files it never had, such as the shared
`abortable-operation` primitive and the `exact-snapshot` decoder that
later fixes are written against. Taking only the newest round was not
possible for that reason: the delta is coherent only as a whole.

The product had not touched `src/adapters` at all since materialization,
so the 140-file delta applied with a three-way merge and no conflicts.
`package.json` was the single overlap and merged cleanly: the product owns
`name`, the template contributed `check:adapter-inventory`,
`check:remediation-ledger` and the image-resolve-signal type fixture.
All 24 product-owned files — README, index.html, CI workflow, i18n
catalog, home page, generated schemas, evidence scripts, component and
visual snapshots — are byte-identical to `main`.

`template.lock.json` now pins the synced revision and tree.

Verified in this repository, not inherited from the template: six type
projects, lint, nine gates (adapter inventory, remediation ledger,
registries, diagnostics, realtime boundaries, architecture, browser
file/storage boundaries, optional recipes, documentation), the production
build, and 2,054 of 2,073 tests. The 19 failures are all in
`tests/unit/ci-artifact-contract.test.ts` and are the same pre-existing
sandbox RLIMIT, EMFILE, umask and `/tmp` permission behaviour the template
records; four suites that failed once under parallel load pass in
isolation.

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

src/adapters/cache-storage/public-cache-policy.ts

@@ -132,6 +132,11 @@ export function assertPublicCachePolicy(
     policy.allowedVaryHeaderNames.some(
       (name) => !policy.allowedRequestHeaderNames.includes(name),
     ) ||
+    // STO-03. Enabling variants while stripping `vary` from stored responses
+    // makes every variant collide on the same cache key, so the combination is
+    // rejected at composition instead of producing an unusable candidate.
+    (policy.allowedVaryHeaderNames.length > 0 &&
+      !policy.allowedResponseHeaderNames.includes("vary")) ||
     policy.forbiddenQueryParameterNames.some((name) => name.length === 0) ||
     policy.allowedQueryParameterNames.some((name) =>
       policy.forbiddenQueryParameterNames.includes(name),