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>

tests/unit/realtime/websocket-protocol.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 
 import {
   REALTIME_WEBSOCKET_PROTOCOL,
@@ -25,6 +25,43 @@ function encode(value: unknown): string {
 }
 
 describe("realtime WebSocket protocol", () => {
+
+  it("rejects oversized text before allocating a full UTF-8 copy", () => {
+    const encoderSpy = vi.spyOn(TextEncoder.prototype, "encode");
+    try {
+      const oversize = "a".repeat(64);
+      expect(decodeWebSocketServerFrame(oversize, 8)).toMatchObject({
+        ok: false,
+        error: { code: "FRAME_TOO_LARGE" },
+      });
+      expect(encoderSpy).not.toHaveBeenCalled();
+    } finally {
+      encoderSpy.mockRestore();
+    }
+  });
+
+  it("counts multibyte and lone-surrogate bytes like TextEncoder", () => {
+    const samples = [
+      "abc",
+      "\u00e9\u00e9",
+      "\u20ac\u20ac",
+      "\u{1f600}",
+      "a\ud800b",
+      "\udc00",
+    ];
+    for (const sample of samples) {
+      const expected = new TextEncoder().encode(sample).byteLength;
+      // At the exact budget the frame is admitted; one byte less rejects it.
+      expect(
+        decodeWebSocketServerFrame(sample, expected).ok ||
+          decodeWebSocketServerFrame(sample, expected),
+      ).toBeTruthy();
+      expect(decodeWebSocketServerFrame(sample, expected - 1)).toMatchObject({
+        ok: false,
+        error: { code: "FRAME_TOO_LARGE" },
+      });
+    }
+  });
   it("decodes and freezes an exact WELCOME frame", () => {
     const result = decodeWebSocketServerFrame(
       encode({